Surajit Sen

{{Use dmy dates|date=September 2023}}

{{Infobox scientist

| name = Surajit Sen

| image =

| image_size =

| caption =

| birth_date = {{birth date and age|1960|11|28}}

| birth_place = Calcutta (now Kolkata), India

| fields = Physics

| workplaces = State University of New York at Buffalo

| alma_mater = University of Georgia (Ph.D., 1990)

| doctoral_advisor = M. Howard Lee

| known_for = Non-equilibrium statistical physics, nonlinear dynamics, solitary waves in granular media

| awards = Fellow of the American Physical Society (2008), Fellow of the American Association for the Advancement of Science (2012)

}}

Surajit Sen (born November 28, 1960, in Calcutta (modern name Kolkata) in India) is a physicist who works on theoretical and computational problems in non-equilibrium statistical physics and in nonlinear dynamics of many body systems. He holds a Ph.D in physics from The University of Georgia (1990) where he studied with M. Howard Lee. He is also interested in applying physics to study problems of relevance in a societal context. He is a professor of physics at the State University of New York, Buffalo.{{Cite web|url=http://www.buffalo.edu/|title=Welcome to the University at Buffalo - University at Buffalo|website=www.buffalo.edu|language=en|access-date=2017-06-22}} Much of Sen's recent work can be found in his RUSA lecture at Bharatidasan University.{{Cite AV media |website=www.youtube.com |access-date=2023-09-13 |title=About Sand, Nonlinear Dynamics and Metamaterials |url=https://www.youtube.com/watch?v=sp9OllzSvSQ}}

Sen is credited with developing an exact solution for the Heisenberg equation of motion in a quantum mechanical many body system in 1991.{{Cite journal|last=Sen|first=Surajit|date=1991-10-01|title=Exact solution of the Heisenberg equation of motion for the surface spin in a semi-infinite S=1/2 XY chain at infinite temperatures|journal=Physical Review B|volume=44|issue=14|pages=7444–7450|doi=10.1103/PhysRevB.44.7444|pmid=9998658|bibcode=1991PhRvB..44.7444S}} His studies include work on how solitary waves travel in alignments of elastic beads,{{Cite journal|last1=Sen|first1=Surajit|last2=Manciu|first2=Marian|last3=Wright|first3=James D.|date=1998-02-01|title=Solitonlike pulses in perturbed and driven Hertzian chains and their possible applications in detecting buried impurities|journal=Physical Review E|volume=57|issue=2|pages=2386–2397|doi=10.1103/PhysRevE.57.2386|bibcode=1998PhRvE..57.2386S}} on how they interact with one another and how these systems{{Cite journal|last1=Manciu|first1=Marian|last2=Sen|first2=Surajit|last3=Hurd|first3=Alan J.|date=2000-12-27|title=Crossing of identical solitary waves in a chain of elastic beads|journal=Physical Review E|volume=63|issue=1|pages=016614|doi=10.1103/PhysRevE.63.016614|pmid=11304385|bibcode=2000PhRvE..63a6614M}}{{Cite journal|last1=Manciu|first1=Felicia S.|last2=Sen|first2=Surajit|date=2002-07-30|title=Secondary solitary wave formation in systems with generalized Hertz interactions|journal=Physical Review E|volume=66|issue=1|pages=016616|doi=10.1103/PhysRevE.66.016616|pmid=12241509|bibcode=2002PhRvE..66a6616M|s2cid=7772700}}{{Cite news|url=https://phys.org/news/2005-05-physicists-undetectable-baby-solitary.html|title=Physicists detect the undetectable: 'baby' solitary waves|access-date=2017-06-23}} tend to reach an equilibrium-like state where equipartitioning of energy is not respected, which he called the quasi-equilibrium state.{{Cite journal|last1=Sen|first1=Surajit|last2=Krishna Mohan|first2=T. R.|last3=M.M. Pfannes|first3=Jan|date=2004-10-15|title=The quasi-equilibrium phase in nonlinear 1D systems|journal=Physica A: Statistical Mechanics and Its Applications|series=Proceedings of the VIII Latin American Workshop on Nonlinear Phenomena|volume=342|issue=1|pages=336–343|doi=10.1016/j.physa.2004.04.092|bibcode=2004PhyA..342..336S}} Suggestion of a similar state was made soon thereafter by Berges et al.{{Cite journal|last1=Berges|first1=J.|last2=Borsányi|first2=Sz.|last3=Wetterich|first3=C.|date=2004-09-28|title=Prethermalization|journal=Physical Review Letters|volume=93|issue=14|pages=142002|doi=10.1103/PhysRevLett.93.142002|pmid=15524783|arxiv=hep-ph/0403234|bibcode=2004PhRvL..93n2002B}} Recently, Neyenhuis et al{{Cite journal|last1=Neyenhuis|first1=Brian|last2=Zhang|first2=Jiehang|last3=Hess|first3=Paul W.|last4=Smith|first4=Jacob|last5=Lee|first5=Aaron C.|last6=Richerme|first6=Phil|last7=Gong|first7=Zhe-Xuan|last8=Gorshkov|first8=Alexey V.|last9=Monroe|first9=Christopher|date=2017-08-01|title=Observation of prethermalization in long-range interacting spin chains|journal=Science Advances|language=en|volume=3|issue=8|pages=e1700672|doi=10.1126/sciadv.1700672|pmid=28875166|pmc=5573308|issn=2375-2548|arxiv=1608.00681|bibcode=2017SciA....3E0672N}} may have found some experimental evidence of this quasi-equilibrium/prethermalization state. Sen's Steel Institute colloquium at the Indian Institute of Technology, Bombay, captures some of his work on strongly nonlinear systems.{{Cite web |title=Non-linear Dynamics and Statistical Physics |url=https://arts-sciences.buffalo.edu/physics/research/non-linear-dynamics-statistical-physics.html |access-date=2025-05-02 |website=University at Buffalo Department of Physics |language=en}}

Recently, his group has also shown how the energy equipartitioned state may in fact be realized in these systems.{{Cite journal|last1=Przedborski|first1=Michelle|last2=Sen|first2=Surajit|last3=Harroun|first3=Thad A.|date=2017-03-06|title=Fluctuations in Hertz chains at equilibrium|journal=Physical Review E|volume=95|issue=3|pages=032903|doi=10.1103/PhysRevE.95.032903|pmid=28415183|arxiv=1605.08970|bibcode=2017PhRvE..95c2903P|s2cid=35302728}} In 1997, he investigated the possible use of sound bursts in detecting buried small landmines.{{cite patent|title=System for detection of buried objects|pubdate=Jul 9, 2002|inventor-last=Sen|inventor2-last=Naughton|inventor-first=Surajit|inventor2-first=Michael J.|country=US|number=6418081}}{{Cite web|url=http://buffalonews.com/1997/12/07/ub-researchers-hope-shocking-work-leads-to-way-to-sound-out-land-mines/|title=UB RESEARCHERS HOPE SHOCKING WORK LEADS TO WAY TO SOUND OUT LAND MINES|date=1997-12-07|website=The Buffalo News|access-date=2017-06-22}}{{Cite journal|last1=Sen|first1=Surajit|last2=Manciu|first2=Marian|last3=Sinkovits|first3=Robert S.|last4=Hurd|first4=Alan J.|date=2001-01-01|title=Nonlinear acoustics in granular assemblies|journal=Granular Matter|language=en|volume=3|issue=1–2|pages=33–39|doi=10.1007/s100350000067|s2cid=59062982|issn=1434-5021}} In 2001, he introduced the tapered granular chain impact dispersion system,{{Cite journal|last1=Sen|first1=Surajit|last2=Manciu|first2=Felicia S.|last3=Manciu|first3=Marian|date=2001-10-15|title=Thermalizing an impulse|journal=Physica A: Statistical Mechanics and Its Applications|volume=299|issue=3|pages=551–558|doi=10.1016/S0378-4371(01)00340-5|bibcode=2001PhyA..299..551S}} which has since been extensively probed.{{Cite journal|last1=Rosas|first1=Alexandre|last2=Lindenberg|first2=Katja|author2-link= Katja Lindenberg |date=2004-03-31|title=Pulse velocity in a granular chain|journal=Physical Review E|volume=69|issue=3|pages=037601|doi=10.1103/PhysRevE.69.037601|pmid=15089450|arxiv=cond-mat/0309070|bibcode=2004PhRvE..69c7601R|s2cid=38733538}}{{Cite journal|last1=Nakagawa|first1=Masami|last2=Agui|first2=Juan H.|last3=Wu|first3=David T.|last4=Extramiana|first4=David Vivanco|date=2003-02-01|title=Impulse dispersion in a tapered granular chain|journal=Granular Matter|language=en|volume=4|issue=4|pages=167–174|doi=10.1007/s10035-002-0119-1|s2cid=120729013|issn=1434-5021}}{{Cite journal|last1=Doney|first1=Robert L.|last2=Agui|first2=Juan H.|last3=Sen|first3=Surajit|date=2009-09-15|title=Energy partitioning and impulse dispersion in the decorated, tapered, strongly nonlinear granular alignment: A system with many potential applications|journal=Journal of Applied Physics|volume=106|issue=6|pages=064905–064905–13|doi=10.1063/1.3190485|issn=0021-8979|bibcode=2009JAP...106f4905D}}{{Cite journal|last1=Harbola|first1=Upendra|last2=Rosas|first2=Alexandre|last3=Romero|first3=Aldo H.|last4=Lindenberg|first4=Katja|author4-link= Katja Lindenberg |date=2010-07-26|title=Pulse propagation in randomly decorated chains|journal=Physical Review E|volume=82|issue=1|pages=011306|doi=10.1103/PhysRevE.82.011306|pmid=20866610|bibcode=2010PhRvE..82a1306H}} Sen has recently suggested that nonlinear systems may be used to extract mechanical energy from noisy environments and make them into useful energy.{{Cite web|url=https://www.nsf.gov/news/news_summ.jsp?cntn_id=121188|title=Research Outlines Math Framework That Could Help Convert 'Junk' Energy Into Useful Power {{!}} NSF - National Science Foundation|website=www.nsf.gov|language=en|access-date=2017-06-23}} Sen's group has used cellular automata based simulations to model land battles between an insurgent army and an intelligent army{{Cite journal|last1=Westley|first1=Alexandra|last2=De Meglio|first2=Nicholas|last3=Hager|first3=Rebecca|last4=Mok|first4=Jorge Wu|last5=Shanahan|first5=Linda|last6=Sen|first6=Surajit|date=2017-03-23|title=Study of simple land battles using agent-based modeling: Strategy and emergent phenomena|journal=International Journal of Modern Physics B|volume=31|issue=10|pages=1742002|doi=10.1142/S0217979217420024|issn=0217-9792|bibcode=2017IJMPB..3142002W}} and used molecular dynamics based simulations to examine the social structure of chimpanzee colonies.{{Cite book|title=Nature's Longest Threads|last1=Westley|first1=Matthew|last2=Sen|first2=Surajit|last3=Sinha|first3=Anindya|date=2014-05-07|publisher=WORLD SCIENTIFIC|isbn=9789814612463|pages=81–102|doi=10.1142/9789814612470_0009}} He has also been active in modeling partisan elections.Tiwari, Mukesh, Xiguang Yang, and Surajit Sen. "Modeling the nonlinear effects of opinion kinematics in elections: A simple Ising model with random field based study." Physica A: Statistical Mechanics and its Applications 582 (2021): 126287.

Sen was elected as a Fellow{{Cite web|url=https://www.aps.org/programs/honors/fellowships/|title=APS Fellowship|website=www.aps.org|language=en|access-date=2017-04-20}} of the American Physical Society{{Cite web|url=https://www.aps.org/programs/honors/fellowships/archive-all.cfm?initial=&year=&unit_id=&institution=|title=APS Fellow Archive|website=www.aps.org|language=en|access-date=2017-04-20}} in 2008,{{Cite web|url=https://www.aps.org/programs/honors/fellowships/archive-all.cfm?initial=&year=2008&unit_id=&institution=|title=APS Fellows 2008|website=www.aps.org|language=en|access-date=2017-04-20}} for the discovery of how solitary waves break and secondary solitary waves form in granular media, for his leadership in organizing forums to represent and recognize the physicists from India and for raising consciousness about the problems and the importance of rural science education in India and the developing world. He was also elected as a Fellow of the American Association for the Advancement of Science in 2012{{Cite news|url=https://www.aaas.org/news/aaas-members-elected-fellows-2|title=AAAS Members Elected as Fellows|date=2012-11-30|work=AAAS - The World's Largest General Scientific Society|access-date=2017-06-22|language=en}} for pioneering research on solitary waves and their collisions in granular media and for sustained outstanding service and leadership in international physics.{{Cite journal|last=Science|first=American Association for the Advancement of|date=2012-11-30|title=AAAS News and Notes|journal=Science|language=en|volume=338|issue=6111|pages=1166–1171|doi=10.1126/science.338.6111.1166|issn=0036-8075|doi-access=free}}

In 2020-2021 he served as a Senior Science Advisor at the United States Agency for International Development while on leave as a Jefferson Science Fellow of the US National Academies. His work is summarized in a JSF Distinguished Lecture presented at the US National Academies https://vimeo.com/566681948. More recently, Sen served as a Distinguished Visiting Professor of Biosciences and Bioengineering at the Indian Institute of Technology Jodhpur, India, where one of his focus areas have been desert ecosystems.