Monday, August 2, 2021

Decent living standards for all while reducing energy use: Per capita, 9 lbs/4 kg of new clothing/year, 177lbs/80 kg of washing/year, 20 washes per year; & 1 phone; per household, a cooker, a fridge, a laptop

Securing decent living standards for all while reducing global energy use. Leeds Univ press release, Jun 2021.

Fundamental changes in our economies are required to secure decent living standards for all in the struggle against climate breakdown, according to new research.


Lead author Jefim Vogel, PhD researcher at Leeds' Sustainability Research Institute, explained: "Decent living standards are crucial for human well-being, and reducing global energy use is crucial for averting catastrophic climate changes. Truly sustainable development would mean providing decent living standards for everyone at much lower, sustainable levels of energy and resource use.

"But in the current economic system, no country in the world accomplishes that - not even close. It appears that our economic system is fundamentally misaligned with the aspirations of sustainable development: it is unfit for the challenges of the 21st century."

Co-author Professor Julia Steinberger, from the University of Leeds and the University of Lausanne in Switzerland, added: "The problem is that in our current economic system, all countries that achieve decent living standards use much more energy than what can be sustained if we are to avert dangerous climate breakdown."

By 2050, global energy use needs to be as low as 27 gigajoules (GJ) of final energy per person to reach the aspirations of the Paris Agreement of limiting global warming to 1.5 °C without relying on speculative future technologies, according to the Intergovernmental Panel on Climate Change. That means current global average energy use (55 GJ per person) needs to be cut in half, while affluent countries like the UK (81 GJ per person) or Spain (77 GJ per person) need to reduce their average energy use by as much as 65%, France (95 GJ per person) by more than 70%, and the most energy-hungry countries like the USA (204 GJ per person) or Canada (232 GJ per person) need to cut by as much as 90%.

A major concern, however, is that such profound reductions in energy use might undermine living standards, as currently only countries with high energy use accomplish decent living standards.

Even the energy-lightest of the countries that achieve decent living standards - spearheaded by Argentina (53 GJ per person), Cyprus (55 GJ per person), and Greece (63 GJ per person) - use at least double the 'sustainable' level of 27 GJ per person, and many countries use even much more.

On the other hand, in all countries with energy use levels below 27 GJ per person, large parts of the population currently suffer from precarious living standards - for example, in India (19 GJ per person) and Zambia (23 GJ per person), where at least half the population is deprived of fundamental needs.

It appears that in the current economic system, reducing energy use in affluent countries could undermine living standards, while improving living standards in less affluent countries would require large increases in energy use and thus further exacerbate climate breakdown.

But this is not inevitable, the research team show: fundamental changes in economic and social priorities could resolve this dilemma of sustainable development.

Co-author Dr Daniel O'Neill, from Leeds' School of earth and Environment, explained: "Our findings suggest that improving public services could enable countries to provide decent living standards at lower levels of energy use. Governments should offer free and high-quality public services in areas such as health, education, and public transport.

"We also found that a fairer income distribution is crucial for achieving decent living standards at low energy use. To reduce existing income disparities, governments could raise minimum wages, provide a Universal Basic Income, and introduce a maximum income level. We also need much higher taxes on high incomes, and lower taxes on low incomes."

Another essential factor, the research team found, is affordable and reliable access to electricity and modern fuels. While this is already near-universal in affluent countries, it is still lacking for billions of people in lower-income countries, highlighting important infrastructure needs.

Perhaps the most crucial and perhaps the most surprising finding is that economic growth beyond moderate levels of affluence is detrimental for aspirations of sustainable development.

Professor Steinberger explained: "In contrast with wide-spread assumptions, the evidence suggests that decent living standards require neither perpetual economic growth nor high levels of affluence.

"In fact, economic growth in affluent or even moderately affluent countries is detrimental for living standards. And it is also fundamentally unsustainable: economic growth is tied to increases in energy use, and thus makes the energy savings that are required for tackling climate breakdown virtually impossible."

"Another detrimental factor is the extraction of natural resources such as coal, oil, gas or minerals - these industries need to be scaled back rapidly."

Lead-author Jefim Vogel concluded: "In short, we need to abandon economic growth in affluent countries, scale back resource extraction, and prioritise public services, basic infrastructures and fair income distributions everywhere.

"With these policies in place, rich countries could slash their energy use and emissions whilst maintaining or even improving living standards; and less affluent countries could achieve decent living standards and end material poverty without needing vast amounts of energy. That's good news for climate justice, good news for human well-being, good news for poverty eradication, and good news for energy security.

[...] In my view, the most promising and integral vision for the required transformation is the idea of degrowth - it is an idea whose time has come."

Paper: Socio-economic conditions for satisfying human needs at low energy use: An international analysis of social provisioning. Jefim Vogel et al. Global Environmental Change, June 29 2021, 102287.


• No country sufficiently meets human needs within sustainable levels of energy use.

• Need satisfaction and associated energy requirements depend on socio-economic setups.

• Public services are linked to higher need satisfaction and lower energy requirements.

• Economic growth is linked to lower need satisfaction and higher energy requirements.

• Countries with good socio-economic setups could likely meet needs at low energy use.


Meeting human needs at sustainable levels of energy use is fundamental for avoiding catastrophic climate change and securing the well-being of all people. In the current political-economic regime, no country does so. Here, we assess which socio-economic conditions might enable societies to satisfy human needs at low energy use, to reconcile human well-being with climate mitigation.

Using a novel analytical framework alongside a novel multivariate regression-based moderation approach and data for 106 countries, we analyse how the relationship between energy use and six dimensions of human need satisfaction varies with a wide range of socio-economic factors relevant to the provisioning of goods and services ('provisioning factors'). We find that factors such as public service quality, income equality, democracy, and electricity access are associated with higher need satisfaction and lower energy requirements (‘beneficial provisioning factors’). Conversely, extractivism and economic growth beyond moderate levels of affluence are associated with lower need satisfaction and greater energy requirements (‘detrimental provisioning factors’). Our results suggest that improving beneficial provisioning factors and abandoning detrimental ones could enable countries to provide sufficient need satisfaction at much lower, ecologically sustainable levels of energy use.

However, as key pillars of the required changes in provisioning run contrary to the dominant political-economic regime, a broader transformation of the economic system may be required to prioritise, and organise provisioning for, the satisfaction of human needs at low energy use.

Check also Providing decent living with minimum energy: A global scenario. Joel Millward-Hopkins, Julia K. Steinberger, Narasimha D. Rao, Yannick Oswald. Global Environmental Change, Volume 65, November 2020, 102168.


• Providing Decent Living with Minimum Energy: A Global Scenario.

• As ecological breakdown looms, the basic material needs of billions remain unmet.

• We estimate the minimal energy for providing decent living globally & universally.

• Despite population growth, 2050 global energy use could be reduced to 1960 levels.

• This requires advanced technologies & reductions in demand to sufficiency levels.

• But ‘sufficiency’ is far more materially generous than many opponents often assume.

Abstract: It is increasingly clear that averting ecological breakdown will require drastic changes to contemporary human society and the global economy embedded within it. On the other hand, the basic material needs of billions of people across the planet remain unmet. Here, we develop a simple, bottom-up model to estimate a practical minimal threshold for the final energy consumption required to provide decent material livings to the entire global population. We find that global final energy consumption in 2050 could be reduced to the levels of the 1960s, despite a population three times larger. However, such a world requires a massive rollout of advanced technologies across all sectors, as well as radical demand-side changes to reduce consumption – regardless of income – to levels of sufficiency. Sufficiency is, however, far more materially generous in our model than what those opposed to strong reductions in consumption often assume.

Keywords: Basic needsClimate changeDemandEnergyInequalitySufficiency

In order to save the planet from catastrophic climate change, Americans will have to cut their energy use by more than 90 percent and families of four should live in housing no larger than 640 square feet. That's at least according to a team of European researchers led by University of Leeds sustainability researcher Jefim Vogel. In their new study, "Socio-economic conditions for satisfying human needs at low energy use," in Global Environmental Change, they calculate that public transportation should account for most travel. Travel should, in any case, be limited to between 3,000 to 10,000 miles per person annually.

Vogel and his colleagues set themselves the goal of figuring out how to "provide sufficient need satisfaction at much lower, ecologically sustainable levels of energy use." Referencing earlier sustainability studies they argue that human needs are sufficiently satisfied when each person has access to the energy equivalent of 7,500 kilowatt-hours (kWh) of electricity per capita. That is about how much energy the average Bolivian uses. Currently, Americans use about 80,000 kWh annually per capita. With respect to transportation and physical mobility, the average person would be limited to using the energy equivalent of 16–40 gallons of gasoline per year. People are assumed to take one short- to medium-haul airplane trip every three years or so.

In addition, food consumption per capita would vary depending on age and other conditions, but the average would be 2,100 calories per day. While just over 10 percent of the world's people are unfortunately still undernourished, the Food and Agriculture Organization reports that the daily global average food supply now stands at just under 3,000 calories per person. Each individual is allocated a new clothing allowance of nine pounds per year, and clothes may be washed 20 times annually. The good news is that everyone over age 10 is permitted a mobile phone and each household can have a laptop.


To achieve [Paris Agreement goals], the researchers focus on what they call provisioning factors, which are intermediary institutions that people use to satisfy their needs. Provisioning factors that affect the amount of energy a society uses include public service, public health coverage, access to electricity and clean fuels, democratic quality, income equality, economic growth, and extractivism. These provisioning factors are the basis for providing sufficient human needs such as nourishment, drinking water, sanitation access, basic education, and a minimum income, all of which help secure the basic need of healthy life expectancy.

In order to stay below the 1.5°C temperature increase threshold, they cite earlier research that calculated that the average person should be limited to using annually as little as 18 gigajoules (equivalent to 136 gallons of gasoline or 5,000 kWh) of total energy, but allocated more generously for their study a cap of 27 gigajoules (equivalent to 204 gallons of gasoline or 7,500 kWh) annually. They then checked to see if any country in the world had met their definition of decent living standards using that amount of energy per capita. "No country in the world accomplishes that—not even close," admitted Vogel in an accompanying press release.


[...] So they proceed to jigger the various provisioning factors until they find that what is really needed is a "more fundamental transformation of the political-economic regime." That fundamental transformation includes free government-provided high-quality public services in areas such as health, education, and public transport.

"We also found that a fairer income distribution is crucial for achieving decent living standards at low energy use," said co-author Daniel O'Neill, from Leeds' School of Earth and Environment. "To reduce existing income disparities, governments could raise minimum wages, provide a Universal Basic Income, and introduce a maximum income level. We also need much higher taxes on high incomes, and lower taxes on low incomes."


Per capita: 9 lbs/4 kg of new clothing/year, 177lbs/80 kg of washing/year, 20 washes per year; 1 phone.

Per household: a cooker, a fridge, a laptop.

From the Millward-Hopkins paper above:
Food2000–2150 kcal/cap/day15%3 KJ/kilocalorie30%
 Cooking appliances1 cooker/household0.8 KJ/kilocalorie1 GJ/app+50%
 Cold Storage1 fridge-freezer/household0.44 GJ/app+/yr4 GJ/app+

Shelter & living conditions
 Household size4 persons/household−25%
 Sufficient space15 meters2 floor-space/cap*80%2–4 GJ/m2100%
 Thermal comfort15 meters2 floor-space/cap*80%20–60 MJ/m2/yr300%
 Illumination2500 lm/house; 6 hrs/day100%150 lm/W14 MJ/house/yr

 Water supply50 Litres/cap/day100%5–17 KJ/L
 Water heating20 Litres/cap/day100%96–220 KJ/L50%
 Waste managementProvided to all households**180 MJ/cap/yr200%

 Clothes4 kg of new clothing/year33%100 MJ/kg
Washing facilities80 kg of washing/year33%2.4 MJ/kg2 GJ/app+
 Healthcare Hospitals200 meters2 floor-space/bed50%410–560 MJ/m2/yr14–23 GJ/m2130%
 Education Schools10 meters2 floor-space/pupil50%100–130 MJ/m2/yr4.5–7.5 GJ/m2150%

Communication & information
 Phones1 phone/person over 10yrs old28 MJ/phone/yr110 MJ/phone30%
 Computers1 laptop/household220 MJ/laptop/yr3 GJ/laptop30%
Networks & dataHigh**100%~0.4 GJ/cap/yr

 Vehicle productionConsistent with pkm travelled**0.1–0.3 MJ/pkm50%
 Vehicle propulsion5000–15,000 pkm/cap/year3–10%0.2–1.9 MJ/pkm++100%
 InfrastructureConsistent with pkm travelled**0.1–0.3 MJ/pkm
* Assuming 10 m2 of living space/capita plus 20 m2 of communal space/house; with the latter divided by four, we get 15 m2/capita overall.
** Activity levels here are not straightforward to define.
+ ’App’ refers to ‘appliance’.
++ Large range as this covers different modes (public transport to passenger flights).

Appearance dissatisfaction is a sensitive issue and has been tied to depression, dissatisfaction in romantic relationships, and reduced sexual satisfaction

Øverup CS, Strizzi JM, Cipric A, et al. Appearance Satisfaction as a Predictor of Specific Sexual Problems and Associated Distress. J Sex Med 2021;XX:XXX–XXX. Aug 2 2021.


Introduction: Appearance dissatisfaction is a sensitive issue and has been tied to depression, dissatisfaction in romantic relationships, and reduced sexual satisfaction.

Aim: This study sought to examine associations between appearance satisfaction and specific sexual problems and related distress, testing also the moderating role of relationship satisfaction.

Methods: A large web-sample of Norwegians in romantic relationships (N = 2,903) completed a one-time survey.

Outcomes: Participants reported on their experience of five different sexual problems and associated level of distress.

Results: We found that appearance satisfaction was associated with reporting fewer sexual problems, and specifically, with a smaller likelihood of experiencing problems with lack of enjoyment, lack of excitement, and lack of climax. Furthermore, appearance satisfaction was unrelated to overall sexual problem-related distress, but was associated with feeling less distress about lack of excitement and lack of climax. Relationship satisfaction did not serve as a moderator of the associations.

Clinical Translation: These findings suggest the importance of attending to appearance satisfaction when working with clients with multiple sexual problems, particularly those related to excitement and enjoyment.

Strengths and Limitations: Strengths of the study include a large sample of partnered adults and assessment of specific sexual problems and associated distress. A limitation is that outcomes were assessed using single items, rather than multi-item scales.

Conclusion: The study highlights the importance of examining the presence of sexual problems and associated distress separately, and to consider appearance satisfaction as a predictor of sexual functioning.

Key Words: Appearance satisfactionBody satisfactionBMISexual problemsSexual dysfunctionSexual distressRelationship satisfaction


The current study is among the first to examine associations between appearance satisfaction and specific sexual problems and associated distress, as well as the cumulative number of sexual problems and overall distress related to any/multiple sexual problems, in a large sample of partnered Norwegian adults. A particular strength of the current study is the ability to look at the presence of specific sexual problems and the associated distress, as opposed to only general assessments of sexual functioning. Indeed, research highlights the distinction between sexual satisfaction and sexual difficulties,59,60 and that people who experience sexual problems may not necessarily experience distress related to those problems, especially at older age.28293031323334353637 Moreover, much existing research has examined physiological predictors of sexual functioning, with a lesser focus on psychosocial factors. However, burgeoning research has begun to examine relational predictors of functioning and associated distress, putting sexual functioning squarely in the domain of relational functioning. The current research adds to this burgeoning field of study, by examining both psychological (appearance satisfaction) and social (relationship satisfaction) factors. In sum, it is important to examine the presence of sexual problems and the level of distress related to sexual problems separately, to understand the potentially disparate predictive ability of various factors, including psychosocial factors.

Number of Sexual Problems and the Presence of Specific Sexual Problems

Results demonstrated that appearance satisfaction was associated with reporting fewer sexual problems (H2), and specifically, with a smaller likelihood of reporting problems with sexual lack of enjoyment, excitement, and climax (H3). These findings are consistent with past research that has found that acceptance of one's body is associated with more sexual enjoyment,17 and that feeling negative about one's body is associated with decrements in orgasm,18,19 and overall sexual functioning61. Interestingly, and contrary to past research,17 we did not find an association between appearance satisfaction and lack of sexual interest (H3). It is unclear why we did not find this association; however, in the present sample, lack of interest was relatively common, with 30% of people endorsing this problem. Thus, it may be that other factors play a larger role than does appearance satisfaction in predicting whether people experience a lack of sexual interest. Factors may include age or sample population. Fooken used a sample of elderly women, while our study included both men and women of all ages.17

We also did not find that appearance satisfaction was associated with feeling anxious during sex (H3). It is noteworthy that only 4% of the sample endorsed this problem, and thus, there may have been too little variability in this sample to examine the association. Conversely, it may be that people experience less anxiety during sex, when the sex is with a committed romantic partner. Future research may wish to examine within a sample of people who all report issues with sexual anxiety whether body and appearance satisfaction predicts the level of sexual anxiety. Indeed, past research suggests that one reason for feeling anxious during sex may be body self-consciousness and an anxious attentional focus on the body.19,20,21,62

Distress Related to Sexual Problems

Results also suggested that appearance satisfaction was unrelated to overall sexual problem-related distress (RQ1) and distress related to sexual lack of interest and enjoyment, and feeling anxious during sex (RQ2). Appearance satisfaction was related to feeling less distress about sexual lack of excitement and climax (RQ2). It may be that the link between appearance dissatisfaction, cognitive distractions, and sexual problems and related distress provides an explanation. Previous research has found that body dissatisfaction is associated with cognitive distractions63 and that body dissatisfaction is associated with distress related to sexual problems. In fact, Pascoal and colleagues64 found that the association between body dissatisfaction and sexual functioning was mediated by cognitive distractions. In contrast to this study64, Pascoal et al. measured overall distress for all/any sexual problems. It could be that lower levels of appearance satisfaction lead to higher levels of cognitive distraction and these are more influential during the arousal and orgasm phases of the sexual response cycle and consequently be associated with higher levels of distress associated with lack of excitement and climax. Future research should examine whether there is a differential effect of body satisfaction and cognitive distractions on the diverse sexual problems and their associated distress. Although these associations are small in magnitude, they represent a first examination of the associations between appearance satisfaction and distress over specific sexual problems. Past research has found that lower appearance dissatisfaction was associated with less sexual problem-related distress;39,64 this research, however, examined general distress and not problem-specific distress.

The Role of Relationship Satisfaction

It is noteworthy that as people reported higher relationship satisfaction, they were less likely to endorse having a sexual problem, but felt more distress over lack of excitement. This is consistent with past research, which has found that relationship satisfaction is associated with better sexual functioning.25,40414243 However, in committed relationships, people may feel that sexual interactions are normative, and thus, they may feel more distressed about lack of excitement for a partner for whom they otherwise care and love. Future research should seek to examine the role of perceptions of sexual norms and expectations in romantic relationships, and their importance in predicting distress associated with sexual problems, particularly problems related to arousal.

Relationship satisfaction was unrelated to the presence of all five specific sexual problems, and unrelated to overall distress and distress related to all other problems (except for distress over lack of excitement). This is inconsistent with past research, which has found that lower relationship satisfaction was associated with greater distress48,65 and greater emotional closeness during sex was associated with less distress35,454647. However, one reason for this lack of associations may be the relatively high levels of relationship satisfaction in the sample. Indeed, the average level of relationship satisfaction was 5.91 out of 7 (see Table 1); thus, there may be have been a ceiling effect that restricted the range in scores, leading to reduced variability. Consequently, we did not find indications of moderation by relationship satisfaction (RQ3a and RQ3b).

The Role of Gender

Much extant research in both sexuality and appearance satisfaction has focused on gender, often examining these construct separately for men and women. Indeed, sexual problems may vary by sex (i.e., men may have issues with erection and ejaculation, while women may have issues with vaginal lubrication and pain during intercourse). Similarly, appearance ideals may vary by gender, as women may strive for thinness and men may strive for muscularity.66 However, it is recognized that, while ideals may vary, both genders experience dissatisfaction with their appearance,2 though research suggests that women experience higher levels of dissatisfaction than do men. One might therefore expect that the association between appearance satisfaction and sexual problems, and associated distress, may be stronger for women, as they may internalize the importance that society places on ideal women's body shapes and appearances.67 However, in the current study, we found that the association did not vary by gender. That is, the associations between appearance satisfaction and the presence of sexual problems, and their associated distress, were not stronger for women than for men, as one might expect. However, we did find general gender differences, such that women were more likely to report sexual problems (though, not consistently higher distress than men). These findings suggest that when appearance satisfaction and sexual problems are assessed in general, men's and women's experiences are similar. Especially considering that recent theory and research suggests that men and women are more similar than they are different across most psychological variables,68,69 this may be relevant in the context to experiences with sexual problems and appearance satisfaction. However, it may be that this pattern of results would be different, if sexual problems and appearance evaluations were assessed in gender-specific ways.

Limitations and Future Directions

There are strengths to the current study, including a large sample of partnered adults and assessment of specific sexual problems along with associated distress. However, the current study should also be viewed in terms of its limitations.

For one, while it is a benefit that we were able to examine individual and specific sexual problems, they were assessed using single items, and not an established scale. This may be a limitation, as sexual problems were addressed generally and not with respect to gender-specific problems, such as problems with erection, ejaculation, vaginal lubrication, or pain during sex. Moreover, single-item measures of sexual satisfaction have the disadvantage of being unidimensional and may have low test-retest reliability.70 Relatedly, appearance satisfaction was assessed using a single item that asked about satisfaction with physical appearance (“fysisk utseende”), and did not use existing scales of body or appearance dissatisfaction71. However, single items (rather than scales) were employed in an effort to maximize response rates and reduce participant burden, and is generally accepted and widely used in the field, as they may capture the construct to a satisfactory degree.72 Moreover, the generality of the items allowed us to assess sexual problems and feelings about appearance that may be relevant to all, regardless of gender.

Moreover, due to the general population sample and concerns about participant burden in responding to survey questions, we did not collect any data regarding any general health concerns, medications (specifically those with possible sexual side effects or appearance-related side effects such as weight gain), sexual pathologies or related therapies. Future research should consider collecting such data, as these can interfere with sexual activity or with body image. Similarly, future research may wish to include extended (and validated) measurement of gender-specific sexual problems, as well as gender-specific appearance evaluations, as such measurements may provide useful information regarding the link between body appearance and sexuality. Some research suggests that evaluation regarding specific body parts may be uniquely associated with sexual functioning73. Future research may also wish to examine potential mediators of the association between appearance satisfaction and sexual functioning. One such mediator may be inhibition/excitation. It has been demonstrated that, in women, self-perceived sexual attractiveness influence sexual responses by acting on the excitation and inhibition response pathways.74

Norwegian Sexual Behavior surveys have been conducted in previous years, yielding responses of 23% in 2008, 34% in 2002, 38% in 1997, 48% in 1992, and 63% in 198775. Thus, a low response rate seems to be a common finding in Norwegian questionnaire surveys. However, the response rate in this survey was higher than that in the 2008 survey. It has been demonstrated that dropout from the survey was unrelated to sexual behaviour, and random rather than systematic.76 As this study had a similar response rate to previous iterations of the survey, there is reason to believe that dropout in this survey also was random rather than systematic.

The data is cross-sectional in nature and therefore, we are precluded from making conclusions about causality. Future research may wish to examine these associations using more naturalistic methods, such as event-contingent diary methods or ecological momentary assessments. Such methods are relatively rare in sex research, though much knowledge is to be gained. That is, such methods allow for an examination of associations between constructs as they occurred in daily life, reducing retrospective bias. Currently, much work focus on general reports of sexual functions and memory of feelings of distress, which may be skewed by recency effects.77 Moreover, as sexual interactions and sexual functioning may be impacted by mood, and many daily and relational events may influence mood, future daily diary research may wish to include a measure of mood, to examine its predictive association with daily sexual functioning and associated distress. Indeed, it may be that mood serves as a mediator of the association between daily relational events and daily sexual functioning and associated distress.

Lastly, consistent with past research,43,78 the current research examined relationship satisfaction as a predictor of sexual problems or sexual functioning. However, it may be that relationship satisfaction may serve as the outcome, such that sexual functioning predicts relationship satisfaction. Likely, there is a bidirectional association between the two, and future research should seek to disentangle the mechanisms underlying this association. Indeed, it may be that the association between appearance satisfaction and relationship satisfaction is moderated by sexual problems, rather than the reverse, as we examined here. Relatedly, situating sexual problems and associated distress in a relational context, it may be interesting to examine the appearance satisfaction and BMI of both partners in a couple. Much research in the relationship sciences has demonstrated the presence of contagion effects79, and such a dynamic may be at play with appearance satisfaction, relationship satisfaction, and sexual problems/distress as well. That is, it may be that individuals who are dissatisfied with their appearance foster appearance dissatisfaction in their partners, and that jointly, this dissatisfaction influence their sexual behavior in negative ways.

Children and adolescents are gradually discovering the dangers hiding behind social interactions & need to come equipped to detect them, assess them, etc.; failures in these abilities are closely related to underdeveloped logical abilities

Steps of Reasoning in Children and Adolescents. Isabelle Brocas and Juan D. Carrillo. Journal of Political Economy, Volume 129, Number 7.

Abstract: We develop a novel graphical paradigm of a strict-dominance-solvable game to study the developmental trajectory of steps of reasoning between 8 years old and adulthood. Most participants play the equilibrium action either always or only when they have a dominant strategy. Although age is a determinant of equilibrium choice, some very young participants display an innate ability to play at equilibrium. Finally, the proportion of equilibrium play increases significantly until fifth grade and stabilizes afterward, suggesting that the contribution of age to equilibrium play vanishes early in life.


Adolescents are particularly exposed to situations in which strategic sophistication is crucial to avoid wrong decisions. Examples include engaging in risky activities, such as accepting drugs from peers or engaging in unprotected sex. Also, with the development of the internet, naive users are often preyed upon, asked to provide personal information, or tricked into making harmful decisions. Information deliberately intended to deceive young minds also circulates through social media. Making correct decisions in such environments requires understanding the intentions of others and anticipating the consequences of following their advice or opinions. More generally, children and adolescents are gradually discovering the dangers hiding behind social interactions and need to come equipped to detect them, assess them, and navigate around them. We conjecture that failures in these abilities are closely related to underdeveloped logical abilities, and we predict that the level of sophistication of an individual detected through a simple task matches their behavior in social settings.

Claim: Like a perpetual motion machine, a time crystal forever cycles between states without consuming energy, evading increasing disorder

Observation of Time-Crystalline Eigenstate Order on a Quantum Processor. Xiao Mi, Matteo Ippoliti, Chris Quintana, Amy Greene, Zijun Chen, Jonathan Gross, Frank Arute, Kunal Arya, Juan Atalaya, Ryan Babbush, Joseph C. Bardin, Joao Basso, Andreas Bengtsson, Alexander Bilmes, Alexandre Bourassa, Leon Brill, Michael Broughton, Bob B. Buckley, David A. Buell, Brian Burkett, Nicholas Bushnell, Benjamin Chiaro, Roberto Collins, William Courtney, Dripto Debroy, Sean Demura, Alan R. Derk, Andrew Dunsworth, Daniel Eppens, Catherine Erickson, Edward Farhi, Austin G. Fowler, Brooks Foxen, Craig Gidney, Marissa Giustina, Matthew P. Harrigan, Sean D. Harrington, Jeremy Hilton, Alan Ho, Sabrina Hong, Trent Huang, Ashley Huff, William J. Huggins, L. B. Ioffe, Sergei V. Isakov, Justin Iveland, Evan Jeffrey, Zhang Jiang, Cody Jones, Dvir Kafri, Tanuj Khattar, Seon Kim, Alexei Kitaev, Paul V. Klimov, Alexander N. Korotkov, Fedor Kostritsa, David Landhuis, Pavel Laptev, Joonho Lee, Kenny Lee, Aditya Locharla, Erik Lucero, Orion Martin, Jarrod R. McClean, Trevor McCourt, Matt McEwen, Kevin C. Miao, Masoud Mohseni, Shirin Montazeri, Wojciech Mruczkiewicz, Ofer Naaman, Matthew Neeley, Charles Neill, Michael Newman, Murphy Yuezhen Niu, Thomas E. O'Brien, Alex Opremcak, Eric Ostby, Balint Pato, Andre Petukhov, Nicholas C. Rubin, Daniel Sank, Kevin J. Satzinger, Vladimir Shvarts, Yuan Su, Doug Strain, Marco Szalay, Matthew D. Trevithick, Benjamin Villalonga, Theodore White, Z. Jamie Yao, Ping Yeh, Juhwan Yoo, Adam Zalcman, Hartmut Neven, Sergio Boixo, Vadim Smelyanskiy, Anthony Megrant, Julian Kelly, Yu Chen et al. (5 additional authors not shown). arXiv Jul 28 2021.

Abstract: Quantum many-body systems display rich phase structure in their low-temperature equilibrium states. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that out-of-equilibrium systems can exhibit novel dynamical phases that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC). Concretely, dynamical phases can be defined in periodically driven many-body localized systems via the concept of eigenstate order. In eigenstate-ordered phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, wherein few select states can mask typical behavior. Here we implement a continuous family of tunable CPHASE gates on an array of superconducting qubits to experimentally observe an eigenstate-ordered DTC. We demonstrate the characteristic spatiotemporal response of a DTC for generic initial states. Our work employs a time-reversal protocol that discriminates external decoherence from intrinsic thermalization, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. In addition, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to study non-equilibrium phases of matter on current quantum processors.

Check also World's first video recording of a space-time crystal | Max Planck Institute for Intelligent Systems (

Popular version: Eternal Change for No Energy: A Time Crystal Finally Made Real. Jul 30 2021.

Like a perpetual motion machine, a time crystal forever cycles between states without consuming energy. Physicists claim to have built this new phase of matter inside a quantum computer.

[Full text, photos, etc.,  at the Quanta link above]

In a preprint posted online Thursday night [Observation of Time-Crystalline Eigenstate Order on a Quantum Processor (], researchers at Google in collaboration with physicists at Stanford, Princeton and other universities say that they have used Google’s quantum computer to demonstrate a genuine “time crystal.” In addition, a separate research group claimed earlier this month to have created a time crystal in a diamond.

A novel phase of matter that physicists have strived to realize for many years, a time crystal is an object whose parts move in a regular, repeating cycle, sustaining this constant change without burning any energy.

“The consequence is amazing: You evade the second law of thermodynamics,” said Roderich Moessner, director of the Max Planck Institute for the Physics of Complex Systems in Dresden, Germany, and a co-author on the Google paper. That’s the law that says disorder always increases. [!!!]  

Time crystals are also the first objects to spontaneously break “time-translation symmetry,” the usual rule that a stable object will remain the same throughout time. A time crystal is both stable and ever-changing, with special moments that come at periodic intervals in time.

The time crystal is a new category of phases of matter, expanding the definition of what a phase is. All other known phases, like water or ice, are in thermal equilibrium: Their constituent atoms have settled into the state with the lowest energy permitted by the ambient temperature, and their properties don’t change with time. The time crystal is the first “out-of-equilibrium” phase: It has order and perfect stability despite being in an excited and evolving state.

“This is just this completely new and exciting space that we’re working in now,” said Vedika Khemani, a condensed matter physicist now at Stanford who co-discovered the novel phase while she was a graduate student and co-authored the new paper with the Google team.

Khemani, Moessner, Shivaji Sondhi of Princeton and Achilleas Lazarides of Loughborough University in the United Kingdom discovered the possibility of the phase and described its key properties in 2015; a rival group of physicists led by Chetan Nayak of Microsoft Station Q and the University of California, Santa Barbara identified it as a time crystal soon after.

Researchers have raced to create a time crystal over the past five years, but previous demos, though successful on their own terms, have failed to satisfy all the criteria needed to establish the time crystal’s existence. “There are good reasons to think that none of those experiments completely succeeded, and a quantum computer like [Google’s] would be particularly well placed to do much better than those earlier experiments,” said John Chalker, a condensed matter physicist at the University of Oxford who wasn’t involved in the new work.

Google’s quantum computing team made headlines in 2019 when they performed the first-ever computation that ordinary computers weren’t thought to be able to do in a practical amount of time. Yet that task was contrived to show a speedup and was of no inherent interest. The new time crystal demo marks one of the first times a quantum computer has found gainful employment.

“It’s a fantastic use of [Google’s] processor,” Nayak said.

With yesterday’s preprint, which has been submitted for publication, and other recent results, researchers have fulfilled the original hope for quantum computers. In his 1982 paper proposing the devices, the physicist Richard Feynman argued that they could be used to simulate the particles of any imaginable quantum system.

A time crystal exemplifies that vision. It’s a quantum object that nature itself probably never creates, given its complex combination of delicate ingredients. Imaginations conjured the recipe, stirred by nature’s most baffling laws.

An Impossible Idea, Resurrected

The original notion of a time crystal had a fatal flaw.

The Nobel Prize­-winning physicist Frank Wilczek conceived the idea in 2012, while teaching a class about ordinary (spatial) crystals. “If you think about crystals in space, it’s very natural also to think about the classification of crystalline behavior in time,” he told this magazine not long after.

Consider a diamond, a crystalline phase of a clump of carbon atoms. The clump is governed by the same equations everywhere in space, yet it takes a form that has periodic spatial variations, with atoms positioned at lattice points. Physicists say that it “spontaneously breaks space-translation symmetry.” Only minimum-energy equilibrium states spontaneously break spatial symmetries in this way.

Wilczek envisioned a multi-part object in equilibrium, much like a diamond. But this object breaks time-translation symmetry: It undergoes periodic motion, returning to its initial configuration at regular intervals.

Wilczek’s proposed time crystal was profoundly different from, say, a wall clock — an object that also undergoes periodic motion. Clock hands burn energy and stop when the battery runs out. A Wilczekian time crystal requires no input and continues indefinitely, since the system is in its ultra-stable equilibrium state.

If it sounds implausible, it is: After much thrill and controversy, a 2014 proof showed that Wilczek’s prescription fails, like all other perpetual-motion machines conceived throughout history.

That year, researchers at Princeton were thinking about something else. Khemani and her doctoral adviser, Sondhi, were studying many-body localization, an extension of Anderson localization, the Nobel Prize-winning 1958 discovery that an electron can get stuck in place, as if in a crevice in a rugged landscape.

An electron is best pictured as a wave, whose height [!!!] in different places gives the probability of detecting the particle there. The wave naturally spreads out over time. But Philip Anderson discovered that randomness — such as the presence of random defects in a crystal lattice — can cause the electron’s wave to break up, destructively interfere with itself, and cancel out everywhere except in a small region. The particle localizes.

People thought for decades that interactions between multiple particles would destroy the interference effect. But in 2005, three physicists at Princeton and Columbia universities showed that a one-dimensional chain of quantum particles can experience many-body localization; that is, they all get stuck in a fixed state. This phenomenon would become the first ingredient of the time crystal.

Imagine a row of particles, each with a magnetic orientation (or “spin”) that points up, down, or some probability of both directions. Imagine that the first four spins initially point up, down, down and up. The spins will quantum mechanically fluctuate and quickly align, if they can. But random interference between them can cause the row of particles to get stuck in their particular configuration, unable to rearrange or settle into thermal equilibrium. They’ll point up, down, down and up indefinitely.

Sondhi and a collaborator had discovered that many-body localized systems can exhibit a special kind of order, which would become the second key ingredient of a time crystal: If you flip all the spins in the system (yielding down, up, up and down in our example), you get another stable, many-body localized state.


In the fall of 2014, Khemani joined Sondhi on sabbatical at the Max Planck Institute in Dresden. There, Moessner and Lazarides specialized in so-called Floquet systems: periodically driven systems, such as a crystal that’s being stimulated with a laser of a certain frequency. The laser’s intensity, and thus the strength of its effect on the system, periodically varies.

Moessner, Lazarides, Sondhi and Khemani studied what happens when a many-body localized system is periodically driven in this way. They found in calculations and simulations that when you tickle a localized chain of spins with a laser in a particular way, they’ll flip back and forth, moving between two different many-body localized states in a repeating cycle forever without absorbing any net energy from the laser.

They called their discovery a pi spin-glass phase (where the angle pi signifies a 180-degree flip). The group reported the concept of this new phase of matter — the first many-body, out-of-equilibrium phase ever identified — in a 2015 preprint, but the words “time crystal” didn’t appear anywhere in it. The authors added the term in an updated version, published in Physical Review Letters in June 2016, thanking a reviewer in the acknowledgments for making the connection between their pi spin-glass phase and time crystals.

Something else happened between the preprint’s appearance and its publication: Nayak, who is a former graduate student of Wilczek’s, and collaborators Dominic Else and Bela Bauer put out a preprint in March 2016 proposing the existence of objects called Floquet time crystals. They pointed to Khemani and company’s pi spin-glass phase as an example.

A Floquet time crystal exhibits the kind of behavior envisioned by Wilczek, but only while being periodically driven by an external energy source. This kind of time crystal circumvents the failure of Wilczek’s original idea by never professing to be in thermal equilibrium. Because it’s a many-body localized system, its spins or other parts are unable to settle into equilibrium; they’re stuck where they are. But the system doesn’t heat up either, despite being pumped by a laser or other driver. Instead, it cycles back and forth indefinitely between localized states.

Already, the laser will have broken the symmetry between all moments in time for the row of spins, imposing instead “discrete time-translation symmetry” — that is, identical conditions only after each periodic cycle of the laser. But then, through its back-and-forth flips, the row of spins further breaks the discrete time-translation symmetry imposed by the laser, since its own periodic cycles are multiples of the laser’s.

Khemani and co-authors had characterized this phase in detail, but Nayak’s group couched it in the language of time, symmetry and spontaneous symmetry-breaking — all fundamental concepts in physics. As well as offering sexier terminology, they provided new facets of understanding, and they slightly generalized the notion of a Floquet time crystal beyond the pi spin-glass phase (noting that a certain symmetry it has isn’t needed). Their paper was published in Physical Review Letters in August 2016, two months after Khemani and company published the theoretical discovery of the first example of the phase.

Both groups claim to have discovered the idea. Since then, the rival researchers and others have raced to create a time crystal in reality.

The Perfect Platform

Nayak’s crew teamed up with Chris Monroe at the University of Maryland, who uses electromagnetic fields to trap and control ions. Last month, the group reported in Science that they’d turned the trapped ions into an approximate, or “prethermal,” time crystal. Its cyclical variations (in this case, ions jumping between two states) are practically indistinguishable from those of a genuine time crystal. But unlike a diamond, this prethermal time crystal is not forever; if the experiment ran for long enough, the system would gradually equilibrate and the cyclical behavior would break down.

Khemani, Sondhi, Moessner and collaborators hitched their wagon elsewhere. In 2019, Google announced that its Sycamore quantum computer had completed a task in 200 seconds that would take a conventional computer 10,000 years. (Other researchers would later describe a way to greatly speed up the ordinary computer’s calculation.) In reading the announcement paper, Moessner said, he and his colleagues realized that “the Sycamore processor contains as its fundamental building blocks exactly the things we need to realize the Floquet time crystal.”

Serendipitously, Sycamore’s developers were also looking for something to do with their machine, which is too error-prone to run the cryptography and search algorithms designed for full-fledged quantum computers. When Khemani and colleagues reached out to Kostya Kechedzhi, a theorist at Google, he and his team quickly agreed to collaborate on the time crystal project. “My work, not only with discrete time crystals but other projects, is to try and use our processor as a scientific tool to study new physics or chemistry,” Kechedzhi said.

Quantum computers consist of “qubits” — essentially controllable quantum particles, each of which can maintain two possible states, labeled 0 and 1, at the same time. When qubits interact, they can collectively juggle an exponential number of simultaneous possibilities, enabling computing advantages.

Google’s qubits consist of superconducting aluminum strips. Each has two possible energy states, which can be programmed to represent spins pointing up or down. For the demo, Kechedzhi and collaborators used a chip with 20 qubits to serve as the time crystal.

Perhaps the main advantage of the machine over its competitors is its ability to tune the strengths of interactions between its qubits. This tunability is key to why the system could become a time crystal: The programmers could randomize the qubits’ interaction strengths, and this randomness created destructive interference between them that allowed the row of spins to achieve many-body localization. The qubits could lock into a set pattern of orientations rather than aligning.

The researchers gave the spins arbitrary initial configurations, such as: up, down, down, up, and so on. Pumping the system with microwaves flipped up-pointing spins to down and vice versa. By running tens of thousands of demos for each initial configuration and measuring the states of the qubits after different amounts of time in each run, the researchers could observe that the system of spins was flipping back and forth between two many-body localized states.

The hallmark of a phase is extreme stability. Ice stays as ice even if the temperature fluctuates. Indeed, the researchers found that microwave pulses only had to flip spins somewhere in the ballpark of 180 degrees, but not exactly that much, for the spins to return to their exact initial orientation after two pulses, like little boats righting themselves. Furthermore, the spins never absorbed or dissipated net energy from the microwave laser, leaving the disorder of the system unchanged.

On July 5, a team based at the Delft University of Technology in the Netherlands reported that they built a Floquet time crystal not in a quantum processor, but out of the nuclear spins of carbon atoms in a diamond. The Delft system is smaller and more limited than the time crystal realized in Google’s quantum processor.

It’s unclear whether a Floquet time crystal might have practical use. But its stability seems promising to Moessner. “Something that’s as stable as this is unusual, and special things become useful,” he said.

Or the state might be merely conceptually useful. It’s the first and simplest example of an out-of-equilibrium phase, but the researchers suspect that more such phases are physically possible.

Nayak argues that time crystals illuminate something profound about the nature of time. Normally in physics, he said, “however much you try to treat [time] as being just another dimension, it is always kind of an outlier.” Einstein made the best attempt at unification, weaving 3D space together with time into a four-dimensional fabric: space-time. But even in his theory, unidirectional time is unique. With time crystals, Nayak said, “this is the first case that I know of where all of a sudden time is just one of the gang.”

Chalker argues, though, that time remains an outlier. Wilczek’s time crystal would have been a true unification of time and space, he said. Spatial crystals are in equilibrium, and relatedly, they break continuous space-translation symmetry. The discovery that, in the case of time, only discrete time-translation symmetry may be broken by time crystals puts a new angle on the distinction between time and space.

These discussions will continue, driven by the possibility of exploration on quantum computers. Condensed matter physicists used to concern themselves with the phases of the natural world. “The focus moved from studying what nature gives us,” Chalker said, to dreaming up exotic forms of matter that quantum mechanics allows.

Update: July 30, 2021

Following the publication of this article, Quanta learned that a separate research group had, on July 5, posted a preprint claiming to have created a time crystal using nine carbon atoms in a diamond. We have updated the article to include this result.