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X-WR-CALNAME;VALUE=TEXT:Department of Physics - Columbia University Physics Department Website : Department Calendar
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UID:calendar.1606.field_event_date.0
SUMMARY:"The strong CP problem and UV instantons"
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180122T141000
DTEND;TZID=US/Eastern:20180122T141000
URL;VALUE=URI:http://physics.columbia.edu/strong-cp-problem-and-uv-instantons
DESCRIPTION:Date: Mon\, 01/22/2018 - 2:10pmLocation: Pupin Hall Theory Center\, 8th \n FloorTheory Seminar [1]\n .... Prateek Agrawal\n \n /Harvard Univesity/\n \n .... "The strong CP problem and UV instantons" [2]\n \n The absence of sizeable CP violation in the strong sector is a long standing \n puzzle. A class of solutions to this problem rely on a global U(1) symmetry \n that is anomalous with QCD. These solutions lead to robust low-energy \n predictions\, for example a massless up quark or a light axion. I will present \n simple extensions to such solutions which can dramatically change these \n low-energy predictions. In our models\, contributions from small instantons \n play a significant role in affecting the low-energy physics while preserving \n the solution to the strong CP problem.\n \n \n \n [1] http://physics.columbia.edu/event-type/theory-seminar\n [2] http://physics.columbia.edu/files/physics/content/Prateek%20Agrawal_flyer.pdf
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UID:calendar.1601.field_event_date.0
SUMMARY:"Unlocking the secrets of the fastest fluid in nature"
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180122T161500
DTEND;TZID=US/Eastern:20180122T161500
URL;VALUE=URI:http://physics.columbia.edu/unlocking-secrets-fastest-fluid-nature
DESCRIPTION:Date: Mon\, 01/22/2018 - 4:15pmLocation: 428 Pupin HallPhysics Colloquium \n [1]\n .... Jorge Noronha\n \n /University of São Paulo/\n \n .... "Unlocking the secrets of the fastest fluid in nature" [2]\n \n Fluid dynamic behavior is observed in radically different systems\, ranging \n from ordinary fluids (such as water) to their exotic counterparts formed in \n ultra-relativistic particle collisions and the strongly interacting matter \n formed in neutron star mergers. Yet\, their description defies physicists and \n mathematicians\, especially when the flow velocities involved are near the \n speed of light. \n \n This talk will present an introduction to the modern applications of fluid \n dynamics\, focusing on the Quark-Gluon Plasma\, the primordial liquid that \n existed microseconds after the Big Bang. First principles calculations that \n have challenged the very foundations of fluid dynamics\, pushing it towards \n the far-from-equilibrium regime\, will be discussed. A new type of \n universality is shown to emerge in systems far from equilibrium via \n non-equilibrium attractor solutions\, first found in relativistic liquids. \n \n \n *About the speaker*\n \n Jorge Noronha received his PhD in theoretical physics from Goethe University \n Frankfurt\, Germany\, in 2007. Following his PhD\, Jorge worked as a \n postdoctoral scientist at Columbia University from 2008-2011 before joining \n the faculty at the University of Sao Paulo\, Brazil\, where he is currently an \n Assistant Professor. Jorge research interests' include\, Quantum \n chromodynamics\, String theory and the holographic duality\, Quark-gluon \n plasma\, and Fluid dynamics and kinetic theory in curved spacetimes. \n \n [1] http://physics.columbia.edu/event-type/physics-colloquium\n [2] http://physics.columbia.edu/files/physics/content/Jorge%20Noronha_flyer_0.pdf
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UID:calendar.1617.field_event_date.0
SUMMARY:"Probing spinon nodal structures in Kitaev spin liquids"
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180123T143000
DTEND;TZID=US/Eastern:20180123T143000
URL;VALUE=URI:http://physics.columbia.edu/probing-spinon-nodal-structures-kitaev-spin-liquids
DESCRIPTION:Date: Tue\, 01/23/2018 - 2:30pmLocation: 705 Pupin HallSpecial Seminar [1]\n .... Natalia Perkins\n \n /University of Minnesota/\n \n .... "Probing spinon nodal structures in Kitaev spin liquids"\n \n The quantum spin liquid (QSL) state of matter is very difficult to detect \n experimentally because it lacks a local order parameter to which common \n probes couple directly. The three defining characteristics of a QSL are \n a topological ground-state degeneracy\, long-range entanglement\, and a \n fractionalization of the fundamental spin degrees of freedom. While the first \n two are not easily accessible by experiment\, fractionalized excitations can \n be detected by means of thermodynamic and dynamical scattering measurements. \n Here we propose that resonant inelastic X-ray scattering (RIXS) is an \n effective probe of the fractionalized excitations in 2D and 3D Kitaev spin \n liquids\, which are quintessential examples of the QSL state [1\,2]. We find \n that RIXS channels\, the spin-conserving and the non-spin-conserving \n RIXS channels do not interfere and give completely different responses. The \n spin-conserving channel picks up exclusively the Majorana sector with a \n pronounced momentum dispersion. In all Kitaev spin liquids\, as a signature \n of symmetry fractionalization\, the spin-conserving response is strongly \n suppressed around the center of the Brillouin zone. The \n non-spin-conserving RIXS channels additionally create immobile fluxes\, \n and the response becomes only weakly momentum dependent. [1] G. Halasz\, \n N.B. Perkins\, J. van den Brink\, PRL 117\, 127203 (2016)[2] G. Halasz\, B. \n Perreault\, N.B. Perkins\, PRL 119\, 097202 (2017)\n \n [1] http://physics.columbia.edu/event-type/special-seminar
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UID:calendar.1607.field_event_date.0
SUMMARY:Theory seminar: Walter Goldberger\, Yale
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180129T141000
DTEND;TZID=US/Eastern:20180129T141000
URL;VALUE=URI:http://physics.columbia.edu/theory-seminar-walter-goldberger-yale
DESCRIPTION:Date: Mon\, 01/29/2018 - 2:10pmLocation: Pupin Hall Theory Center\, 8th \n FloorTheory Seminar [1]\n .... Walter Goldberger\n \n /Yale University/\n \n *Title & abstract TBA*\n \n \n [1] http://physics.columbia.edu/event-type/theory-seminar
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BEGIN:VEVENT
UID:calendar.1586.field_event_date.0
SUMMARY:"Schrödinger Cats\, Maxwell’s Demon and Quantum Error Correction (That \n Works)"
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180129T161500
DTEND;TZID=US/Eastern:20180129T161500
URL;VALUE=URI:http://physics.columbia.edu/schr%C3%B6dinger-cats-maxwell%E2%80%99s-demon-and-quantum-error-correction-works
DESCRIPTION:Date: Mon\, 01/29/2018 - 4:15pmLocation: 428 Pupin HallPhysics Colloquium \n [1]\n .... Steven Girvin\n \n /Yale University/\n \n .... "Schrödinger Cats\, Maxwell’s Demon and Quantum Error Correction (That\n Works)"\n \n A ‘second quantum revolution’ is underway based on our new understanding \n of how information can be stored and manipulated using quantum hardware. \n Even more remarkable than the concept of quantum computation is the concept \n of quantum error correction. We know that measurement disturbs a quantum \n state. Nevertheless\, it is possible to store an unknown quantum state and \n if it develops errors due to imperfect hardware\, we can measure and correct \n such errors to recover the original unknown state (without ever knowing what \n the state is).\n \n A recent experiment at Yale storing quantum information in Schrödinger cat \n states of microwave photons has successfully demonstrated quantum error \n correction that for the first time enhances the lifetime of the information. \n This talk will present an elementary introduction to the field as well as an \n overview of recent experimental progress.\n \n \n \n \n *About the speaker*\n \n Steven Girvin is a theoretical physicist who studies the quantum mechanics of \n large collections of atoms\, molecules and electrons such as are found in \n superconductors\, magnets and transistors. Of particular current interest to \n him is the engineering question of whether it is possible to build a quantum \n computer. He is collaborating with experimentalists Rob Schoelkopf and Michel \n Devoret in Applied Physics who are constructing superconducting circuit \n elements which might someday form the basis for a quantum computer. Such a \n computer could in principle solve problems which are impossible on ordinary \n computers. However in order to build a quantum computer it is necessary to \n create circuit devices which behave quantum mechanically (like individual \n atoms) despite the fact that they are macroscopic and consist of a very large \n number of atoms. In addition to potential practical applications\, this \n difficult challenge will help us better understand the connections between \n the microscopic quantum world and the macroscopic classical world of everyday \n experience. Professor Girvin is interested in quantum many-body physics\, and \n quantum and classical phase transitions\, particularly in disordered systems. \n A quantum phase transition is one which occurs at zero temperature as some \n parameter in the Hamiltonian is varied. Using path integral techniques\, one \n can often show that a quantum critical point in a d-dimensional system is in \n the same universality class as some other classical system in \n (d+1)-dimensions. He is interested in finding quantities that are universal \n properties of the system near the critical point and are independent of all \n microscopic details. For example\, the electrical conductivity of some \n two-dimensional conductors at critical points is a universal dimensionless \n number of order unity times the quantum of conductance\, e2/h. Much of his \n work has been on the quantum Hall effect\, but he has also worked on the \n superconductor-insulator transition\, the vortex glass transition in high Tc \n superconductors\, superfluid helium in fractal aerogel\, the Anderson \n localization problem\, the Coulomb blockade problem in mesoscopic device \n physics\, and on quantum spin chains. His work is approximately evenly \n divided between analytical theories and numerical simulations.\n \n [1] http://physics.columbia.edu/event-type/physics-colloquium
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BEGIN:VEVENT
UID:calendar.1608.field_event_date.0
SUMMARY:“An analytical approach to eccentric binary mergers”
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180205T141000
DTEND;TZID=US/Eastern:20180205T141000
URL;VALUE=URI:http://physics.columbia.edu/%E2%80%9C-analytical-approach-eccentric-binary-mergers%E2%80%9D
DESCRIPTION:Date: Mon\, 02/05/2018 - 2:10pmLocation: Pupin Hall Theory Center\, 8th \n FloorTheory Seminar [1]\n .... Zhong-Zhi Xianyu\n \n /Harvard University/\n \n .... “An analytical approach to eccentric binary mergers”\n \n Binary black holes in hierarchical triples\, potentially abundant in globular \n clusters and galactic nuclei\, could show up in LIGO and future gravitational \n wave detectors with observably large eccentricity. Measuring the eccentricity \n distribution accurately could help us better understand the background and \n the formation of the mergers. In this talk\, I describe a semi-analytical \n description of eccentricity distribution of mergers in galactic nuclei and \n other hierarchical triple systems. The result could be useful for \n statistically distinguishing different formation channels of observed binary \n mergers\, and also further reduces the reliance on numerical simulations.\n \n \n \n [1] http://physics.columbia.edu/event-type/theory-seminar
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BEGIN:VEVENT
UID:calendar.1570.field_event_date.0
SUMMARY:Colloquium: John Doyle\, Harvard
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180205T161500
DTEND;TZID=US/Eastern:20180205T161500
URL;VALUE=URI:http://physics.columbia.edu/colloquium-john-doyle-harvard
DESCRIPTION:Date: Mon\, 02/05/2018 - 4:15pmLocation: 428 Pupin HallPhysics Colloquium \n [1]\n .... John Doyle\n \n /Harvard University/\n \n Title & abstract TBA\n \n \n [1] http://physics.columbia.edu/event-type/physics-colloquium
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BEGIN:VEVENT
UID:calendar.1609.field_event_date.0
SUMMARY:"A cosmological open quantum system"
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180212T141000
DTEND;TZID=US/Eastern:20180212T141000
URL;VALUE=URI:http://physics.columbia.edu/cosmological-open-quantum-system
DESCRIPTION:Date: Mon\, 02/12/2018 - 2:10pmLocation: Pupin Hall Theory Center\, 8th \n FloorTheory Seminar [1]\n .... Sarah Shandera\n \n /Penn State University/\n \n .... "A cosmological open quantum system"\n \n Our cosmological observations today are limited to a finite volume of space\, \n but models of the primordial universe predict a universe much larger than \n what we see. Those models also predict that quantum fluctuations are the \n origin of the structure in the universe. I will use this framework as \n motivation to construct the evolution equation for the density matrix of an \n infrared-limited set of co-moving momentum modes in two examples of nearly de \n Sitter universes. Including an interaction term from the gravitational action \n and tracing out long-wavelength modes\, I will show that the nature of the \n resulting dissipation terms depends on how curvature fluctuations evolve on \n scales larger than the Hubble scale. The results are relevant for \n constructing effective quantum theories for early universe cosmology\, aswell \n as for other settings where usual UV effective field theory is not \n applicable. \n \n [1] http://physics.columbia.edu/event-type/theory-seminar
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BEGIN:VEVENT
UID:calendar.1571.field_event_date.0
SUMMARY:Colloquium: Antoine Georges\, Ecole Polytechnique
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180212T161500
DTEND;TZID=US/Eastern:20180212T161500
URL;VALUE=URI:http://physics.columbia.edu/colloquium-antoine-georges-ecole-polytechnique
DESCRIPTION:Date: Mon\, 02/12/2018 - 4:15pmLocation: 428 Pupin HallPhysics Colloquium \n [1]\n .... Antoine Georges\n \n /Ecole Polytechnique/\n \n Title & abstract TBA\n \n \n [1] http://physics.columbia.edu/event-type/physics-colloquium
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BEGIN:VEVENT
UID:calendar.1610.field_event_date.0
SUMMARY:Theory seminar: Raphael Bousso\, UC Berkeley
DTSTAMP:20180121T063324Z
DTSTART;TZID=US/Eastern:20180219T141000
DTEND;TZID=US/Eastern:20180219T141000
URL;VALUE=URI:http://physics.columbia.edu/theory-seminar-raphael-bousso-uc-berkeley
DESCRIPTION:Date: Mon\, 02/19/2018 - 2:10pmLocation: Pupin Hall Theory Center\, 8th \n FloorTheory Seminar [1]\n .... Raphael Bousso\n \n /University of California\, Berkeley/\n \n *Title & abstract TBA*\n \n \n [1] http://physics.columbia.edu/event-type/theory-seminar
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