A short video explaining the circumstances under which P.A.M. Dirac left Cambridge for Florida State University (and why Dirac’s grave isn’t in Westminster Abbey, just a commemorative plaque).

[via Graham Farmelo's twitter]

The video and slides for my talk for undergraduates at FermiLab can be found here:

Quantum Effects in Photosynthesis [RealPlayer video link].

This is a good introduction to my research. If you are curious about what I do, by all means watch it.

[I know RealPlayer is so 1998 and sucks, I'm trying to get the file in another format from the FermiLab people.]

Ten summers ago I was an intern in FermiLab, then the largest particle accelerator in the world. I had a fantastic time working with my mentor, Chandra Bhat, to figure out how to accelerate anti-protons in the Main Injector. That summer I learned a lot of physics that motivated me into pursuing a graduate degree in physics. I also made friends I still keep (and even publish with!). And, I was in the poster.

Can you spot me? Hint: Baby-face, clean shaven, short hair.

Yesterday, I went to visit the lab! The organizer from the program, many whom are still working since back in the day, were very kind to invite me there. It was fun to see Naperville again (it hasn’t changed much, suburbia has been yuppiefied a bit) and FermiLab itself (still the same!). I gave a talk titled Quantum Effects in Photosynthesis to a standing-room-only audience of summer interns, high school students, high school teachers and more. It was fantastic to see everyon again, and to interact with the very gifted students. The best questions came from the high school students who seem like they will become very talented scientists and engineers.

The Theorist of Theorist, the first modern physicists who decided theorists were at the forefront of physics, the great P.A.M. Dirac, is the inspiration for the title of this blog, and is one of my heroes!

If you are even slighty curious of who Dirac is, you must know that Steve Mirsky of Scientific American recently interviewed Graham Farmelo, author of the authoritative biography of P.A.M. Dirac, The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom. The interviews is fantastic, full of incredible insight from Graham Farmelo about Dirac’s life and a surprising deep understanding of the importance of Dirac’s work by Steve Mirsky. The interview can be downloaded free online: Part One and Part Two. The funny anecdotes alone are reason enough to check this out. This is the best science interview I have heard in a long time.

To celebrate this interview, SciAm has posted online the article written by Dirac for Scientific American published on 1963. Amazing stuff!

SciAm: If you do this a couple more times, you might inspire hope on me that there might be some good science for laymen magazine out there that isn’t crap.

—

God used beautiful mathematics in creating the world.
-P.A.M. Dirac

The QuEBS conference is on its third wonderful day. The conference has been incredible so far, a series of amazing speakers talking on everything from photosynthesis, the sense of smell, bird navigation and quantum information.

This thursday, the second conference on Quantum Effects in Biological System will be held here at Harvard University. We are very excited to have experts from all over the world here. The aim of this series of conferences is to establish the new field of Quantum Biology. The conference program can be found here.

I’ve received a couple of emails announcing travel grants for conferences, in case you got the travel bug.

US NSF Travel Grant Program for Nordita/Mittag-Leffler

Conference on Quantum Information Theory 4-8 Oct. 2010

This program will provide funds to support travel and lodging for US scientists to participate in the International Conference on Quantum Information Theory to be held in Stockholm Sweden during 4-8 October 2010.  Information on the conference is available at

http://agenda.albanova.se/conferenceDisplay.py?confId=1440

The program is contingent on funding expected from the US National Science Foundation and will be administered by Tufts University.  It is intended to cover most of the costs of travel and lodging.

In addition, funds are available to cover lodging for 1-2 weeks before or after the conference to participate in the fall programs at Nordita and Mittag-Leffler or to engage in collaborative research at other institutes in Scandanavia.  For information on these programs see   http://www.nordita.org/ http://www.mittag-leffler.se/programs/future/1011f/

Those not constrained by teaching obligations are encouraged to take advantage of this opportunity.

Eligibility:  Open to US scientists, i.e., US citizens or those affiliated with a US institution.

• Preference will be given to junior scientists (advanced graduate students and recent PhD’s) and faculty at undergraduate (RUI) institutions.  Members of under-represented groups are especially encouraged to apply.

• In general, those who have current grants with travel funds are not eligible. Partial institutional support is permissible.

• US scientists participating in the Nordita or Mittag-leffler programs in Sept. or Oct. who wish to extend their stay to include the conference week are eligible for lodging support that week.

• Transatlantic travel must use US flag carriers (even if more expensive).

Application process:  Applications must be submitted by e-mail to Chris King   c.king at neu.edu

Send a CV with a cover letter containing a brief description of research interests.   Those who want to extend their stay should also describe their plans and/or interest in this.  Graduate students and new PhD’s should arrange for one (at most two) letters of recommendation to be sent separately.

Application Deadline:   15 July 2010

Selection Process:  Applications will be reviewed by a selection committee of Charles H. Bennett, Alan Aspuru-Guzik,  Julio Gea-Banacloche,  Christopher King (chair),  Marius Junge, Mary Beth Ruskai (PI) and Wim van Dam.   We expect to notify applicants by the start of August.

Questions:  Contact the PI, Mary Beth Ruskai, by e-mail to  marybeth.ruskai at tufts.edu

2010 MICHIGAN QUANTUM SUMMER SCHOOL

The 2010 Michigan Quantum Summer School on Quantum Simulation and Metrology has funding available to host ~60 students.  There is no registration fee and a double-occupancy dorm room is provided at no cost, however transportation and dining expenses need to be covered by the attendees.  We still have ~20 positions available for students or postdocs.  Please forward this email to interested members of your research group and direct them to the website below for registration prior to June 15, 2010.

Thanks,

Aaron Leanhardt

2010 MICHIGAN QUANTUM SUMMER SCHOOL

August 2-13, 2010, Ann Arbor, MI

Organizers: Aaron Leanhardt, Luming Duan, Hui Deng, and Christopher Monroe

http://www.umich.edu/~mctp/SciPrgPgs/events/2010/MQSS10/index.html

The 2010 Michigan Quantum Summer School will serve as an exploratory workshop on Quantum Simulation and Metrology. The summer school is designed to serve a graduate student and postdoc audience, although all are welcome to attend. The school will be held Aug. 2-13, 2010 in Ann Arbor, MI, with a registration date of June 15, 2010. The workshop will cover simulation of many-body, strongly-correlated systems with controllable quantum platforms as well as classical computers, squeezed state and entangled state preparation, and their use to achieve high-precision measurements and to implement quantum information processing.  For further information, including invited speakers and registration, please see the website above.

A few days ago we posted a new paper.

General Bound on the Rate of Decoherence [arXiv:10045405]

Cesar A. Rodriguez-Rosario, Gen Kimura, Hideki Imai, Alan Aspuru-Guzik

We establish the necessary and sufficient conditions for a quantum system to be stable under any general system-environment interaction. Quantum systems are stable when the time-derivative of their purity is zero. This stability provides a dynamical explanation of the classicality of measurement apparatus. We also propose a protocol to detect global quantum correlations using only local dynamical information. We show how quantum correlations to the environment provide bounds to the purity rate, which in turn can be used to estimate dissipation rates for general non-Markovian open quantum systems.

[SciRate]

The paper could have been alternatively titled: “Necessary and Sufficient Conditions for System Stability Under Any Coupling to the Environment”. In this post, I want to discuss briefly our first result of the paper:

.

We were interested in finding universal decoherence stability criteria that depended on the structure of the system-environment state, but was independent of the particular Hamiltonian dynamics. We focused on the measure of decoherence called “Purity”, in particular the rate of change of purity. We found that there exist system-environment states that preserve the purity of the system independent of the details of the interaction Hamiltonian. These states are given by the commutator in the equation above vanishing, and we call them “Stable System States” or SSS for lack of a better name.

SSS states are sparse topologically and not-dense: they are quite rare. But, at the same time, they include states whose system part looks very classical. On first sight, since they are rare, this would raise the question of why does the world looks classical to us. However, the equation above also implies that these states are stable under decoherence, and thus can be long-lived.

In other words, we can prove how classical states emerge naturally in the world without any assumptions of the dynamics! This provides a non-equilibrium thermodynamical explanation to why our universe looks classical.

Reuter’s ScienceWatch recently posted an interview with Prof. Daniel Lidar from USC where they discuss Daniel’s most important papers, focusing on decoherence free subspaces. Daniel was very kind to mention my own work on Open Quantum Systems with initial correlations during the interview.

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“The theory of its operation is rudimentary and attempts to improve its performance are still made in an almost haphazard way”
-Sadi Carnot on engines

I spent last week in Portland for the APS March meeting. It was one of my favorite APS meetings so far. First, the city has some free public transportation, is walkable, and very fun. I got to see many old friends. And I ended up giving two talks.

The first talk was on our PRL paper Time-Dependent Density Functional Theory for Open Quantum Systems with Unitary Propagation.

The session was very interesting, with many proposals for how to expand the realm of applicability of TD-DFT. My boss was supposed to give this talk, but ended up canceling his trip at the last minute.

The second talk was on our paper Linear assignment maps for correlated system-environment states.

This talk was part of the OQS and Decoherence session. For some reason, this session is always on Friday afternoon, which is always the least attended day at the APS, as many leave the conference early. Can this be changed? Still, I got all the usual questions about negative maps, so people were somewhat interested.

How are the sessions organized? How are the days chosen, how are the talks in the session organized? I don’t know. Hopefully, next year, my talk will be at a reasonable day and time.

—

At dawn of day, when you dislike being called, have this thought ready: “I am called to man’s labour; why then do I make a difficulty if I am going out to do what I was born to do and what I was brought into the world for? Is it for this that I am fashioned, to lie in bedclothes and keep myself warm?”  “But this is more pleasant.”  “Were you born then to please yourself; in fact for feeling, not for action? Can’t you see the plants, the birds, the ants, the spiders, the bees each doing his own work, helping for their part to adjust a world? And then you refuse to do a man’s office and don’t make haste to do what is according to your own nature.” “But a man needs rest as well.”
-Marcus Aurelius’ Meditations, on how hard it is for a roman emperor to get up in the morning