Ode to a Flower: Richard Feynman’s Famous Monologue on Knowledge and Mystery, Animated | Brain Pickings

Ode to a Flower: Richard Feynman’s Famous Monologue on Knowledge and Mystery, Animated | Brain Pickings

by Maria Popova

“The science knowledge only adds to the excitement, the mystery and the awe of a flower.”

Richard Feynman — champion of scientific culture, graphic novel hero, crusader for integrity, holder of the key to science, adviser of future generations, bongo player, no ordinary genius. In this fantastic animated adaptation of an excerpt from Christopher Sykes’s celebrated 1981 BBC documentary about Feynman, The Pleasure of Finding Things Out — which gave us the great physicist’s timeless words on beauty, honors, and curiosity and his fascinating explanation of where trees actually come from — Fraser Davidson captures in stunning motion graphics Feynman’s short, sublime soliloquy on why knowledge enriches life rather than detracting from its mystery, the best thing since that animated adaptation of Carl Sagan’s Pale Blue Dot.

The message at the heart of Feynman’s monologue — to celebrate the beauty of the mysterious, embrace the unfamiliar, and life the questions — is beautiful mantra on which to center the new year.

I have a friend who’s an artist and has sometimes taken a view which I don’t agree with very well. He’ll hold up a flower and say “look how beautiful it is,” and I’ll agree. Then he says “I as an artist can see how beautiful this is but you as a scientist take this all apart and it becomes a dull thing,” and I think that he’s kind of nutty. First of all, the beauty that he sees is available to other people and to me too, I believe… 

I can appreciate the beauty of a flower. At the same time, I see much more about the flower than he sees. I could imagine the cells in there, the complicated actions inside, which also have a beauty. I mean it’s not just beauty at this dimension, at one centimeter; there’s also beauty at smaller dimensions, the inner structure, also the processes. The fact that the colors in the flower evolved in order to attract insects to pollinate it is interesting; it means that insects can see the color. It adds a question: does this aesthetic sense also exist in the lower forms? Why is it aesthetic? All kinds of interesting questions which the science knowledge only adds to the excitement, the mystery and the awe of a flower. It only adds. I don’t understand how it subtracts.

Scientists Petition U.S. Congress for Return to the Moon | Space.com

Original article:  http://www.space.com/24068-destination-moon-petition-congress.html?cmpid=514648

by Leonard David, SPACE.com’s Space Insider Columnist   |   December 23, 2013 03:32pm ET

 

China’s Chang’e 3 robotic landing on the moon has helped spur a political crusade in the United States to more aggressively explore and utilize the moon.

At the heart of the campaign is the Lunar Exploration Analysis Group (LEAG), a group chartered by NASA Headquarters to assist in planning the scientific exploration of the moon.  LEAG is organizing a letter writing campaign to Congress to underscore the importance of the moon.

The LEAG scripted strategy is being orchestrated under the banner “Destination Moon” with a key, straightforward goal highlighted in a flyer: “Use the moon to create a sustained human space-faring capability, advancing exploration of the Solar System.” [See photos from China's first moon lander and rover]
  The flyer is to be sent, along with a cover letter, to all members of the U.S. House of Representatives and Senate committees that have influence on NASA funding, and to all the lawmakers of the LEAG executive committee members.

Gateway to the solar system
“We were waiting to see if Chang’e 3 landed successfully and it did! Now we want to champion the moon from the U.S. side,” Clive Neal, a leading lunar scientist at the University of Notre Dame’s Department of Civil and Environmental Engineering and Earth Sciences told SPACE.com. He is a member of LEAG’s executive committee.

The Destination Moon movement is predicated on the value of exploring the moon, from opening the gateway to the solar system, pioneering development of new technologies, as well as advancing economic expansion, enabling new scientific discoveries and promoting international partnerships.
“The moon is the most accessible destination for realizing commercial, exploration, and scientific objectives beyond low Earth orbit,” the flyer reads.

Destination Moon supporters are rallying around other key points:

• Lunar resources can be used for fuel and life support for operations in Earth-moon space as well as for voyages to Mars and beyond.
• America can still lead the world beyond low Earth orbit by forging collaborations to make the frontier of space accessible to all.
• Scientific investigations on the surface of the moon uniquely support studies of early Solar System events that have been erased from Earth’s record.

Nearest near-Earth object

Stephen Mackwell, director of the Lunar and Planetary Institute in Houston, advocates a return to the moon.
“The brief Apollo missions were terminated before we could start investigating the requirements for longer term missions away from Earth,” Mackwell told SPACE.com.

“Before we set off to distant destinations, like Mars, it makes sense to use our nearest near-Earth object — the moon — as a test-bed to see how humans will cope with longer duration periods distant from Earth, including on the surface of another planetary body, and how effectively we can make use of in-situ resources to sustain our presence elsewhere,” Mackwell said. [NASA's 17 Apollo Moon Missions in Pictures]

Political boost
Independent of the LEAG letter writing campaign, a U.S. return to the moon is getting a political boost from Rep. Frank Wolf (R-VA).

In a Dec. 19 letter to President Barack Obama, the lawmaker calls on the president to hold a White House conference early in 2014 to develop a mission concept for a U.S.-led return to the moon within the next 10 years. The conference would bring together “the best minds from around the country and among our international partners” to forge the initiative, Wolf said.

“As China prepares to send a series of increasingly advanced rovers to the moon in preparation for what most observers believe will ultimately be human missions, many are asking why the U.S. is not using this opportunity to lead our international partners in an American-led return to the moon,” Wolf said.

Wolf’s letter said that the Obama administration’s “recalcitrance in leading a lunar mission is creating a crisis of confidence in the U.S. space program, both at home but also among our partners, including Europe, Canada, Japan and Russia.”

In his three-page letter, Wolf urges Obama to direct the U.S. space program toward a “lunar-focused human exploration program that will reaffirm America's space leadership for the 21st Century.”

Lunar development
How United States politics and China’s moon landing of Chang’e 3 play together is far from clear, said Mike Gold, director of Wash., D.C. Operations and Business Growth for Bigelow Aerospace, a private space firm eager to kick up its own commercial lunar dust.

“The success of this mission was yet another victory for long-term Chinese aerospace planning, progress, and execution,” Gold said. “Chinese leadership clearly understands the importance and potential benefits of lunar activities and we here at home ignore the moon at our own peril.”
Gold told SPACE.com that it’s not a matter of ifthe moon will be utilized for commercial activities, it’s a matter of when and who will enjoy those benefits.

“The moon represents an unparalleled commercial opportunity, and Congress should be looking for ways to expand commercial space operations beyond low-Earth orbit," Gold said. "I hope Chang’e 3 inspires a renewed effort for commercial lunar development but I’m afraid the lack of reaction in Washington speaks volumes."

Scientific Groupthink and a Summary of the Evidence that most Published Research is False

If these articles are both true, then are Americans right to distrust scientists and their claims?

http://www.american.com/archive/2013/december/scientific-groupthink-and-gay-parenting

Part one:  Scientific Groupthink

 

By Richard E. ReddingWednesday, December 18, 2013

Filed under: Science & Technology

The controversy over a recent study on gay parenting illustrates a sociopolitical groupthink operating in the social scientific community. Scientists should go where the science takes them, not where their politics does. University of Texas sociology professor Mark Regnerus’s study, “How Different Are the Adult Children of Parents Who Have Same-Sex Relationships? Findings from the New Family Structures Study,” published in the academic journal Social Science Research last year, caused a firestorm in the scientific community. Unlike most previous studies, Regnerus found that children of parents who had experienced a same-sex relationship fared worse than children of heterosexual parents on measures of social, emotional, and psychological adjustment as well as educational attainment, employment history, need for public assistance, substance abuse, and criminal justice system involvement. The reaction to the Regnerus study was swift and harsh. Many of his academic colleagues said it was fatally flawed. Many questioned the motives of the author, reviewers, and journal editor. Did they have an anti-gay political agenda? The controversy illustrates how tougher standards for assessing scientific worth are applied if a study produces results that are inconsistent with the scientists’ own political views. Suppose Regnerus had conducted an identical study, with the same methodological flaws, that had produced results consistent with previous studies, finding no differences between the children of gay or lesbian ("lesbigay") versus heterosexual parents. Would this one study (among the over 60 studies on lesbigay parenting) receive the same criticism, or any criticism at all, from the academic community? Would 201 scholars send a letter to the journal objecting to its publication of the study? Would the author’s former department chair publish an op-ed saying that she was “furious” about her junior colleague’s “pseudo-science”? Would academics make allegations in blogs and other forums about the integrity of the author, journal editor, and editorial review process?1 Would the professor’s university subject him to an intrusive investigation for possible scientific misconduct (of which it found no evidence)? And would similar attacks have been launched against other researchers who dared to question the scholarly consensus?2 Conservatives’ trust in science has dipped to an all-time low. This is not the first time that science has clashed with politics. The Bell Curve, a book about the heritability of intelligence and the resulting libertarian or conservative policy implications, created great controversy. The Regnerus case unfolded similarly to the controversy surrounding the publication of a meta-analysis of child sexual abuse studies that was published in the journal Psychological Bulletin and reported that childhood sexual abuse often caused few long-lasting psychological effects. The article caused outrage. The study was attacked as substandard, and many questioned the authors’ motives and alleged scientific misconduct. Most would acknowledge that science, particularly policy-relevant social science, is often politicized. The Regnerus controversy illustrates that scientists’ sociopolitical views frequently affect the kind of science that is conducted on policy-relevant questions, how findings are interpreted and received, and the degree of critical scrutiny such studies receive. Scientific Groupthink “If when a study yields an unpopular conclusion it is subjected to greater scrutiny, and more effort is expended towards its refutation, an obvious bias to ‘find what the community is looking for’ will have been introduced.”3 The Regnerus case illustrates a sociopolitical groupthink operating in the social scientific community. Surveys of the professoriate consistently find faculties to be quite lopsidedly liberal. The political imbalance is particularly acute in the social sciences, with liberal-conservative ratios of between 8:1 to 30:1 in most disciplines, and particularly with respect to social issues like gay marriage. Such homogeneity of sociopolitical views among social scientists almost invariably leads to “groupthink,” a phenomenon that occurs when group members have relatively homogeneous backgrounds or ideological views. With this groupthink comes self-censorship and pressure on dissenters, the negative stereotyping and discounting of conservative perspectives, and a failure to consider conservative-friendly (as compared with liberal-friendly) question framing and data interpretation. A recent national survey of psychology professors found that one in four reported that they would be less likely to give a positive recommendation on a journal manuscript or grant application having a conservative perspective, and one in six would be less likely to invite conservative colleagues to participate in a symposium. In sociology, Notre Dame University Sociology Professor Christian Smith notes that:   The temptation . . . to advance a political agenda is too often indulged in sociology, especially by activist faculty in certain fields, like marriage, family, sex, and gender ... Research programs that advance narrow agendas compatible with particular ideologies are privileged ... the influence of progressive orthodoxy in sociology is evident in decisions made by graduate students, junior faculty, and even senior faculty about what, why, and how to research, publish, and teach ... The result is predictable: Play it politically safe, avoid controversial questions, publish the right conclusions. Regnerus did not, however, play it safe. He did not publish the right conclusions on a politically controversial topic. Politically correct sociologists, on the other hand, enjoy certain privileges in a very politically conscious and liberal discipline. Indeed, there sometimes is the belief “that social science should be an instrument for social change and thus should promote the ‘correct’ values and ideological positions.”4 No wonder there is so little research by academics that arguably supports conservative policy perspectives. When such research is published, the Regnerus controversy illustrates how it may be received. Critics used the liberal norms and privileges of their discipline to marginalize the Regnerus study. A point-by-point methodological comparison of the Regnerus study alongside previous lesbigay parenting studies reveals the selective scrutiny applied by the critics of the Regnerus study.5 Ideological Diversity Is the Antidote “No one knows how many research programs [social scientists] have failed to launch, or how many research discoveries they have failed to make, as a result of the skew in the distribution of [political] views within their discipline.”6 Contrary to the critics’ concerns about the political conservatism of Regnerus and his funders, the Regnerus study illustrates the value of ideological diversity among both researchers and funders. The allegedly conservative researcher Regnerus, funded by advocacy organizations opposing gay marriage, conducted a study producing findings useful to gay marriage opponents. Many previous studies were conducted and/or funded by those favoring gay marriage, and they produced findings useful to the gay-marriage cause. Scientists should go where the science takes them, not where their politics does. It is not surprising, nor is it indicative of nefarious scientific misconduct, that researchers of different ideological persuasions would produce findings consistent with their own ideology. It is human nature to frame research questions and interpret findings in ways that confirm one’s political beliefs. Such biases are the norm, even among scientists. This is particularly true when it comes to research on social issues because social scientists, many of whom were attracted to social science because of its progressive ideology, often have values invested in the issues they research. One can find such ideological tilt throughout social science research. For instance, how researchers interpret data on the relative contributions of hereditary factors versus environment to intelligence, or on biological factors in personality styles, seems to be partly a function of their political views. Politics inevitably enter into the scientific endeavor as a consequence of the sociopolitical, parochial, financial, or career interests of researchers, funders, and professional organizations as well as those of the larger scientific community and polity. Scientists’ values and interests influence how they define and conceptualize social and behavioral issues, the data collection and analysis methods chosen, how results are interpreted, how scientists scrutinize and evaluate a study’s quality, and whether there are incentives or disincentives to advance research findings in policy advocacy. Because biases are endemic to the scientific enterprise, the Regnerus case illustrates how research conducted or funded by those outside the sociopolitical mainstream, insofar as social scientists are concerned, may be the only way that “politically incorrect” research challenging the scientific consensus gets done. Theoretical or ideological homogeneity among researchers tends to produce myopic, one-sided research, whereas ideological diversity fosters a more dynamic climate that encourages unorthodox, diverse (and sometimes politically incorrect) research. Not only do those in the political minority bring diverse perspectives to the research endeavor, but their very presence has the effect of widening perspective and reducing bias in the rest of the scientific community. If social scientists were embedded in ideologically diverse networks of other scientists, they would be more likely to consider and test alternative hypotheses and perspectives on the social issues they research. Science and Scientists in the Policy Debate “Social scientists are never more revealing of themselves than when challenging the objectivity of one another’s work. In some fields almost any study is assumed to have a more or less discoverable political purpose.”7 Especially with controversies like the Regnerus study, it is no wonder that policymakers of all political persuasions are often skeptical about policy research coming from the academy, or that conservatives’ trust in science has dipped to an all-time low. This is what happens when policy-relevant research fails to be politically inclusive because virtually everyone funding and doing the research comes from the same political perspective. Social scientists, many of whom were attracted to social science because of its progressive ideology, often have values invested in the issues they research. Indeed, scientists who do research on policy issues arguably have an obligation to inform policymakers and the public about their research findings. But it is dangerous for science, policymaking, and the public’s trust in science when scientists are encouraged to do so only when the science supports liberal positions but are discouraged from doing so, or risk disapprobation from their colleagues, when the findings do not. Sadly, this is often the case. Scientists should go where the science takes them, not where their politics does. To attack a study based on the political incorrectness of its findings or its author’s and funder’s politics is scientifically irrelevant and ad hominem. Rather, studies must stand or fall on the weight of their methodological reliability and validity. Part Two:  A summary of the evidence that most published research is false A summary of the evidence that most published research is false Posted on December 16, 2013 by Jeff Leek One of the hottest topics in science has two main conclusions: Most published research is false There is a reproducibility crisis in science The first claim is often stated in a slightly different way: that most results of scientific experiments do not replicate. I recently got caught up in this debate and I frequently get asked about it. So I thought I'd do a very brief review of the reported evidence for the two perceived crises. An important point is all of the scientists below have made the best effort they can to tackle a fairly complicated problem and this is early days in the study of science-wise false discovery rates. But the take home message is that there is currently no definitive evidence one way or another about whether most results are false. Paper: Why most published research findings are false. Main idea: People use hypothesis testing to determine if specific scientific discoveries are significant. This significance calculation is used as a screening mechanism in the scientific literature. Under assumptions about the way people perform these tests and report them it is possible to construct a universe where most published findings are false positive results. Important drawback: The paper contains no real data, it is purely based on conjecture and simulation. Paper: Drug development: Raise standards for preclinical research. Main idea: Many drugs fail when they move through the development process. Amgen scientists tried to replicate 53 high-profile basic research findings in cancer and could only replicate 6. Important drawback: This is not a scientific paper. The study design, replication attempts, selected studies, and the statistical methods to define "replicate" are not defined. No data is available or provided. Paper: An estimate of the science-wise false discovery rate and application to the top medical literature. Main idea: The paper collects P-values from published abstracts of papers in the medical literature and uses a statistical method to estimate the false discovery rate proposed in paper 1 above. Important drawback: The paper only collected data from major medical journals and the abstracts. P-values can be manipulated in many ways that could call into question the statistical results in the paper. Paper: Revised standards for statistical evidence. Main idea: The P-value cutoff of 0.05 is used by many journals to determine statistical significance. This paper proposes an alternative method for screening hypotheses based on Bayes factors. Important drawback: The paper is a theoretical and philosophical argument for simple hypothesis tests. The data analysis recalculates Bayes factors for reported t-statistics and plots the Bayes factor versus the t-test then makes an argument for why one is better than the other. Paper: Contradicted and initially stronger effects in highly cited research Main idea: This paper looks at studies that attempted to answer the same scientific question where the second study had a larger sample size or more robust (e.g. randomized trial) study design. Some effects reported in the second study do not match the results exactly from the first. Important drawback: The title does not match the results. 16% of studies were contradicted (meaning effect in a different direction). 16% reported smaller effect size, 44% were replicated and 24% were unchallenged. So 44% + 24% + 16% = 86% were not contradicted. Lack of replication is also not proof of error. Paper: Modeling the effects of subjective and objective decision making in scientific peer review. Main idea: This paper considers a theoretical model for how referees of scientific papers may behave socially. They use simulations to point out how an effect called "herding" (basically peer-mimicking) may lead to biases in the review process. Important drawback: The model makes major simplifying assumptions about human behavior and supports these conclusions entirely with simulation. No data is presented. Paper: Repeatability of published microarray gene expression analyses. Main idea: This paper attempts to collect the data used in published papers and to repeat one randomly selected analysis from the paper. For many of the papers the data was either not available or available in a format that made it difficult/impossible to repeat the analysis performed in the original paper. The types of software used were also not clear. Important drawback: This paper was written about 18 data sets in 2005-2006. This is both early in the era of reproducibility and not comprehensive in any way. This says nothing about the rate of false discoveries in the medical literature but does speak to the reproducibility of genomics experiments 10 years ago. Paper: Investigating variation in replicability: The "Many Labs" replication project. (not yet published) Main idea: The idea is to take a bunch of published high-profile results and try to get multiple labs to replicate the results. They successfully replicated 10 out of 13 results and the distribution of results you see is about what you'd expect (see embedded figure below). Important drawback: The paper isn't published yet and it only covers 13 experiments. That being said, this is by far the strongest, most comprehensive, and most reproducible analysis of replication among all the papers surveyed here. I do think that the reviewed papers are important contributions because they draw attention to real concerns about the modern scientific process. Namely We need more statistical literacy We need more computational literacy We need to require code be published We need mechanisms of peer review that deal with code We need a culture that doesn't use reproducibility as a weapon We need increased transparency in review and evaluation of papers Some of these have simple fixes (more statistics courses, publishing code) some are much, much harder (changing publication/review culture). The Many Labs project (Paper 8) points out that statistical research is proceeding in a fairly reasonable fashion. Some effects are overestimated in individual studies, some are underestimated, and some are just about right. Regardless, no single study should stand alone as the last word about an important scientific issue. It obviously won't be possible to replicate every study as intensely as those in the Many Labs project, but this is a reassuring piece of evidence that things aren't as bad as some paper titles and headlines may make it seem. Many labs data. Blue x's are original effect sizes. Other dots are effect sizes from replication experiments (http://rolfzwaan.blogspot.com/2013/11/what-can-we-learn-from-many-labs.html)   The Many Labs results suggest that the hype about the failures of science are, at the very least, premature. I think an equally important idea is that science has pretty much always worked with some number of false positive and irreplicable studies. This was beautifully described by Jared Horvath in this blog post from the Economist.  I think the take home message is that regardless of the rate of false discoveries, the scientific process has led to amazing and life-altering discoveries.

State Lawmaker Calls Arizona A 'Desert Racist Wasteland' After Football Loss

Link:  State Lawmaker Calls Arizona A 'Desert Racist Wasteland' After Football Loss

The Huffington Post  |  By Ashley Alman Posted: 12/22/2013 10:54 pm EST  |  Updated: 12/23/2013 10:43 am EST

  

A Washington state lawmaker took poor sportsmanship a bit far following a loss by his home team to the Arizona Cardinals on Sunday.

The Cardinals beat the Seattle Seahawks in a 17-10 win Sunday afternoon, ending their opponents' 14-game home-field winning streak. Shortly following the game, Washington state Rep. Joe Fitzgibbon (D-Burien) took to Twitter to trash talk the victors.

"Losing a football game sucks," Fitzgibbon wrote, according to the Associated Press' Mike Baker. "Losing to a desert racist wasteland sucks a lot."

The Democratic representative deleted the tweet shortly after, sending out the following message:

In an interview, Fitzgibbon explained to Baker that Washington citizens "have not appreciated" Arizona's treatment of immigrants through discriminatory legislation such as Senate Bill 1070, which requires officers to question the immigration status of those suspected to be in the country illegally. He said the state's lawmakers should consider revisiting legislation that leads to racial profiling.

Al Qaeda "apologises" for Yemen hospital attack after gunman kills innocent doctors and nurses

 

Al Qaeda apologise for Yemen hospital attack after gunman kills innocent doctors and nurses

dailymail.co.uk

Shocking CCTV footage shows an Al Qaeda fighter shooting unarmed hospital staff in the head during an attack on the Defence Ministry compound in Yemen.

I don't suppose he's going to apologize for the 3000 innocent Americans they murdered, and for forcing America into a war in Afghanistan that has taken many more innocent Afghan, Pakistani, and Yemen lives (please don't blame the US: no 9/11, no all the other killings). Frankly, no rational person for one moment believes in your "apology", except as a pure political maneuver to gain sympathizers in the West (which you will no doubt succeed at). And people who have forfeited the right to life by their repeated inhumanities do not deserve to, and never will, live free -- those few who survive, that is.

 TODAY -- Pictured: Phil Robertson appears on NBC News' 'Today' show -- (Photo by:   PeterKramer/NBC/NBC NewsWire via Getty Images) | NBC NewsWire via Getty Images

        

Let me get this right. During an interview, Robertson makes the anti-gay, racist (and un-Christian in my view) statements below. He gets understandably fired from his job, just anyone else would, but somehow becomes a hero and martyr to right-wing Christians and their deluded followers everywhere -- only in America (I hope).

From Wikipedia
 "On December 18, 2013, A&E announced an indefinite suspension of Robertson after comments he made about his personal beliefs while being interviewed b...y Drew Magary of GQ.[20] During the interview for a featured article in GQ's January 2014 issue, titled, "What the Duck?"; Magary asked Robertson: "What, in your mind, is sinful?"[21] Answering, Robertson said: Start with homosexual behavior and just morph out from there. Bestiality, sleeping around with this woman and that woman and that woman and those men." Robertson continued by questioning the appeal of same-sex relationships, particularly amongst men; saying: "It seems like, to me, a vagina—as a man—would be more desirable than a man’s anus. That’s just me. I’m just thinking: There’s more there! She’s got more to offer. I mean, come on, dudes! You know what I’m saying? But hey, sin: It’s not logical, my man. It’s just not logical." Robertson went on to say “We never, ever judge someone on who’s going to heaven, hell. That’s the Almighty’s job. We just love ’em, give ’em the good news about Jesus—whether they’re homosexuals, drunks, terrorists. We let God sort ’em out later, you see what I’m saying?”[20][22][23][24] In response to A&E's suspension, Robertson released a statement, saying in part: "I would never treat anyone with disrespect just because they are different from me."[25]

"Robertson also drew criticism for his racial views which he expressed in the same interview. Robertson remarked that being black in Louisiana during the pre-civil rights era was not all that bad, stating:

"I never, with my eyes, saw the mistreatment of any black person. Not once. Where we lived was all farmers. The blacks worked for the farmers. I hoed cotton with them. I’m with the blacks, because we’re white trash. We’re going across the field .... They’re singing and happy. I never heard one of them, one black person, say, ‘I tell you what: These doggone white people’—not a word! ... Pre-entitlement, pre-welfare, you say: Were they happy? They were godly; they were happy; no one was singing the blues.

"In response, the LGBT civil rights advocacy group Human Rights Campaign and the African-American civil rights organization NAACP wrote a joint letter to the president of A&E calling Robertson's remarks dangerous and inaccurate."

Tunable symmetry breaking and helical edge transport in a graphene quantum spin Hall state

Nature | Letter by
A. F. Young,^{1, 3}

J. D. Sanchez-Yamagishi,^{1, 3} 

B. Hunt,^{1, 3}  

S. H. Choi,¹  

K. Watanabe,²

T. Taniguchi,²

R. C. Ashoori¹

Jarillo-Herrero¹  

 

Original Article at:  http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12800.html

 

Nature (2013) doi:10.1038/nature12800 Received  12 July 2013  Accepted  22 October 2013  Published online  22 December 2013

 

Low-dimensional electronic systems have traditionally been obtained by electrostatically confining electrons, either in heterostructures or in intrinsically nanoscale materials such as single molecules, nanowires and graphene. Recently, a new method has emerged with the recognition that symmetry-protected topological (SPT) phases^{1, 2}, which occur in systems with an energy gap to quasiparticle excitations (such as insulators or superconductors), can host robust surface states that remain gapless as long as the relevant global symmetry remains unbroken. The nature of the charge carriers in SPT surface states is intimately tied to the symmetry of the bulk, resulting in one- and two-dimensional electronic systems with novel properties. For example, time reversal symmetry endows the massless charge carriers on the surface of a three-dimensional topological insulator with helicity, fixing the orientation of their spin relative to their momentum^{3, 4}. Weakly breaking this symmetry generates a gap on the surface⁵, resulting in charge carriers with finite effective mass and exotic spin textures⁶. Analogous manipulations have yet to be demonstrated in two-dimensional topological insulators, where the primary example of a SPT phase is the quantum spin Hall state^{7, 8}. Here we demonstrate experimentally that charge-neutral monolayer graphene has a quantum spin Hall state^{9, 10} when it is subjected to a very large magnetic field angled with respect to the graphene plane. In contrast to time-reversal-symmetric systems⁷, this state is protected by a symmetry of planar spin rotations that emerges as electron spins in a half-filled Landau level are polarized by the large magnetic field. The properties of the resulting helical edge states can be modulated by balancing the applied field against an intrinsic antiferromagnetic instability^{11, 12, 13}, which tends to spontaneously break the spin-rotation symmetry. In the resulting canted antiferromagnetic state, we observe transport signatures of gapped edge states, which constitute a new kind of one-dimensional electronic system with a tunable bandgap and an associated spin texture.