Department Calendar

April 2017

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CANCELED - Theory Seminar: Alexander Zamolodchikov, Rutgers

CANCELED - Theory Seminar: Alexander Zamolodchikov, Rutgers

Date: 
Mon, 04/03/2017 - 2:10pm
Location: 
Pupin Hall Theory Center, 8th floor

** Please note:  The theory seminar of Alexander Zamolodchikov will not take place Monday (April 3) **

Please join us on Monday, April 3, 2017, as Alexander Zamolodchikov of Rutgers University gives his talk.

Title & abstract TBA

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04/03/2017 - 2:10pm
 
"Chiral symmetry breaking, emergent Higgs mechanism, and critical matter"

"Chiral symmetry breaking, emergent Higgs mechanism, and critical matter"

Date: 
Mon, 04/03/2017 - 4:15pm
Location: 
428 Pupin

Please join us Monday, April 3, 2017, as Leo Radzihovsky of University of Colorado Boulder gives his colloquium:

"Chiral symmetry breaking, emergent Higgs mechanism, and critical matter"

The upshot of extensive studies of fluctuations is that their qualitative importance is typically confined to isolated critical points of continuous transitions between phases of matter. This conventional wisdom also predicts the number of low energy Goldstone modes based on the so-called “G/H” pattern of symmetry breaking. I will discuss a class of systems, some quite well-known, that violate this standard paradigm. Namely, they exhibit a fewer than “G/H” number of low-energy modes due to an emergent Higgs mechanism. Even more spectacularly, such systems exhibit “critical” ordered phases, with universal power-law properties reminiscent of a critical point, but requiring no fine-tuning and extending throughout the ordered phase. One exciting recently discovered example is the heliconical nematic, that in addition to above phenomena also undergoes spontaneous chiral symmetry breaking.

About the speaker

Leo Radzihovsky was born in St. Petersburg, Russia in 1966. He received B.S., and M.S. degrees in Physics from Rensselaer Polytechnic Institute in 1988, and M.S. and Ph.D. from Harvard University in 1989, and 1993, respectively. He was an Apker fellow (1988) and at Harvard was supported by Hertz Graduate Fellowship. From 1993-1995 Radzihovsky worked as a postdoctoral fellow at the University of Chicago. Since 1995, he has been with the University of Colorado at Boulder, where he is currently a Professor in the Department of Physics. His current research interests include degenerate atomic gases, soft-condensed matter (such as liquid crystals, membranes and polymers), superconductivity, magnetism and general questions that arise in condensed matter systems, especially fluctuation phenomena, disorder, phase transitions, topological defects and nonequilibrium dynamics. Radzihovsky is a Sloan and Packard Fellow and is a Simons Investigator. His research is supported by the National Science Foundation and by the James Simons Foundation.

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04/03/2017 - 4:15pm
 
 
 
"Enhancing superconductivity through optical modulation"

"Enhancing superconductivity through optical modulation"

Date: 
Thu, 04/06/2017 - 4:10pm
Location: 
329 Pupin Hall

Speaker:  Andrea Cavalleri, Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany

When:  Thursday, April 6, 2017

Location & Time:  329 Pupin Hall, 4:10 PM

Title:  "Enhancing superconductivity through optical modulation"

Abstract:

In this talk, I will discuss how coherent electromagnetic radiation at TeraHerz frequencies can be used to coherently modulate the properties of a solid, and to enhance its coherence.

I will specifically focus on Hight Tc cuprates and on molecular compounds like K3C60, and will discuss how optical excitation of specific vibrational modes appears to induce superconducting-like properties at temperatures far in excess of equilibrium Tc.

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04/06/2017 - 4:10pm
 
 
 
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“Massive Gravitons and Time-Dependent Black Holes”
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04/10/2017 - 2:10pm
 
"Strongly Interacting Fermi Gases under the Microscope"

"Strongly Interacting Fermi Gases under the Microscope"

Date: 
Mon, 04/10/2017 - 4:15pm

Please join us Monday, April 10, 2017, as Martin Zwierlein of MIT gives his colloquium:

"Strongly Interacting Fermi Gases under the Microscope"

Strongly interacting fermions govern the physics of e.g. high-temperature superconductors, nuclear matter and neutron stars. The interplay of the Pauli principle with strong interactions can give rise to exotic properties that we do not even understand at a qualitative level. In recent years, ultracold Fermi gases of atoms have emerged as a pristine platform for the creation and study of strongly interacting systems of fermions. Near Feshbach resonances, such gases display superfluidity at 17% of the Fermi temperature. Scaled to the density of electrons in solids, this corresponds to superfluidity far above room temperature. Confined in optical lattices, fermionic atoms realize the Fermi-Hubbard model, believed to capture the essence of cuprate high-temperature superconductors. In recent experiments on two-dimensional Fermi gases under a microscope, we observe metallic, Mott insulating and band insulating states with single-site, single-atom resolution. The microscope allows for the site-resolved detection of charge and spin correlations, revealing the famous Pauli and correlation hole for low and intermediate lattice fillings, and correlated doublon-hole pairs near half filling. These correlations should play an important role for transport in the Fermi-Hubbard model.

About the speaker

Martin Zwierlein studied physics at the University of Bonn and at the Ecole Normale Supérieure in Paris. His doctoral thesis in the group of Wolfgang Ketterle at MIT focused on the observation of superfluidity in ultracold fermionic gases, a novel form of strongly interacting matter. After a postdoctoral stay at the University of Mainz in the group of Immanuel Bloch, he joined the MIT physics department in 2007. His group is using ultracold atomic gases to study models of many-body physics relevant for condensed matter, nuclear and astrophysics. He and his team recently observed Fermi polarons and the quantum limit of diffusion in strongly interacting Fermi gases. His awards include the Klung-Wilhelmy-Weberbank-Prize, Freie Universität Berlin (2007), Young Investigator Awards from the Air Force Office of Scientific Research, the Office of Naval Research and DARPA (2010), a David and Lucile Packard Fellowship (2010) and a Presidential Early Career Award for Scientists and Engineers (2010).

 

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04/10/2017 - 4:15pm
 
"Bose condensation of excitons in a transition metal dichalcogenide"

"Bose condensation of excitons in a transition metal dichalcogenide"

Date: 
Tue, 04/11/2017 - 4:10pm
Location: 
329 Pupin Hall

Speaker:  Peter Abbamonte, University of Illinois

When:  Tuesday, April 11, 2017

Location & Time:  329 Pupin Hall, 4:10 PM

Title:  "Bose condensation of excitons in a transition metal dichalcogenide"

Abstract:

Bose condensation has shaped our understanding of macroscopic quantum phenomena, having been realized in superconductors, atomic gases, and liquid helium. Excitons are bosons that have been predicted to condense into either a superfluid or an insulating electronic crystal. But definitive evidence for a thermodynamically stable exciton condensate has never been achieved. In this talk I will describe our use of momentum-resolved electron energy-loss spectroscopy (M-EELS) to study the valence plasmon in the transition metal dichalcogenide semimetal, 1T‐TiSe2. Near the phase transition temperature, TC = 190 K, the plasmon energy falls to zero at nonzero momentum, indicating dynamical slowing down of plasma fluctuations and crystallization of the valence electrons into an exciton condensate. At low temperature, the plasmon evolves into an amplitude mode of this electronic crystal. Our study represents the first observation of a soft plasmon in any material, the first definitive evidence for exciton condensation in a three-dimensional solid, and the discovery of a new form of matter, “excitonium.”

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04/11/2017 - 4:10pm
 
 
 
"The collisionless life of our Universe"
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04/14/2017 - 11:00am
 
 
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"Large field inflation from the top down"

"Large field inflation from the top down"

Date: 
Mon, 04/17/2017 - 2:10pm
Location: 
Pupin Hall Theory Center, 8th floor

Please join us on Monday, April 17, 2017, as Marjorie Schillo of KU Leuven gives her talk.

"Large field inflation from the top down"

I will present recent work that has succeeded in embedding a novel theory for large field inflation - Unwinding Inflation - in string theory. I will review Unwinding Inflation and discuss how the process of brane-flux annihilation, in which D-branes lower flux numbers and therefore the 4D vacuum energy, can be used to embed this model in string theory. This mechanism has recently been extended such that many units of flux can be discharged in a “flux cascade.” The flux cascade can be used to substantially reduce vacuum energy and give rise to 60 efolds of inflation.  The role of the inflaton is played by the position of a brane moving many times over a compact internal dimension and can naturally achieve super-Planckian field excursions.

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04/17/2017 - 2:10pm
 
"From Mott Physics to Topology"

"From Mott Physics to Topology"

Date: 
Mon, 04/17/2017 - 4:15pm
Location: 
428 Pupin Hall

Alessandra Lanzara

Physics Department, University California, Berkeley

Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley

"From Mott Physics to Topology"

Two types of interactions commonly drive new emergent phenomena beyond textbook band theory in quantum materials: electron correlation and spin orbit coupling. The first, born from the observation of Mott that strong electron correlation can drive a system, otherwise metallic, on the verge of being an insulator, has excited the condensed matter community over the past several decades and lies at the core of many unsolved phenomena, such as unconventional superconductivity. The second, derives from the relativistic correction to the hydrogen-like atom, and has been vastly explored in the previous decades in the context of Rashba effect. Recently, the realization that strong spin orbit coupling can induce dramatic effect on the band structure of weakly interacting systems driving new phases of matter such as the topological band insulators has sparked huge interest in this emerging field. The real frontier today is to understand whether strongly interacting systems can exhibit any type of intrinsic topological order, distinct from band topology in insulators and what consequences this might have.

In this talk I will present experimental results for a variety of materials spanning the entire range of interaction, from strong correlation (Mott insulators), to strong spin orbit coupling (topological insulators) and intermediate interaction regime (spin orbit coupled Mott insulators). I will present intriguing results on the interplay between these two interactions and how, even in the most extreme case they can give rise to unexpected topological like features. The future of the field is discussed.

About the speaker

Alessandra Lanzara is a Professor of Physics at University of California, Berkeley and a Faculty Scientist at the Lawrence Berkeley National Laboratory. She received her B.S and PhD in physics from Universita' di Roma La Sapienza, Italy in 1999. She was a post-doctoral Researcher at Stanford University from 1999-2002. In 2002 she joined the physics Department faculty at UC Berkeley as Assistant Professor and since 2011 she is a Full Professor. She is also a Faculty Scientist at the Materials Sciences Division of the Lawrence Berkeley National Laboratory since 2002. Prof. Lanzara is one of the board members of the Far West Section of the American Physical Society; serves as a Panel member of the Linar Coherent Light Source at Stanford; as an Advisory Member of the "Scientific Council of the Rome International Center for Material Science"; and as a board member of the Photon Science Advisory Committee of the Paul Scherer Institute in Switzerland. She is also serving on the board of a few prestigious scientific journals.

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04/17/2017 - 4:15pm
 
 
 
 
"Latest results and future potential of Japanese long baseline neutrino oscillation experiments"

"Latest results and future potential of Japanese long baseline neutrino oscillation experiments"

Date: 
Fri, 04/21/2017 - 11:00am
Location: 
705 Pupin Hall

Please join us on Friday, April 21, 2017, as Professor Takashi Kobayashi of Institute for Particle and Nuclear Studies (IPNS), KEK, Japan gives his talk.

"Latest results and future potential of Japanese long baseline neutrino oscillation experiments"

(slides)

The T2K experiment is a long baseline neutrino oscillation experiment in Japan using the high intensity proton accelerator J-PARC as the neutrino beam source and Super-Kamiokande (SK) at 295 km from J-PARC as the far neutrino detector. T2K started data taking in 2010 and the accelerator is now running at 470 kW, accumulating ~2.1e21 protons on target (POT). The latest results will be presented.

The next phase of T2K, "T2K-II", to increase the data to ~20e21POT with a J-PARC upgrade to 1.3 MW will be presented. T2K-II can find the first evidence of CP violation in the neutrino sector by more than 3 sigma if CP symmetry is maximally violated (CP delta = -90 deg) with the full statistics.

Hyper-Kamiokande (HK) is the next generation large water Cherenkov detector in Kamioka. We aim to begin construction in 2018 and completion by 2026 to start operation. The fiducial mass is 190 kt x 2 tanks (SK = 22.5 kt). With the HK detector and high intensity neutrino beam from 1.3 MW J-PARC, HK can find CP violation at >3 sigma for 80% region of the CP delta parameter space. Future potential of HyperKamiokande project will be presented.

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04/21/2017 - 11:00am
 
 
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"Theories of bad metals"

"Theories of bad metals"

Date: 
Mon, 04/24/2017 - 2:10pm
Location: 
Pupin Hall Theory Center, 8th floor

Please join us on Monday, April 24, 2017, as Sean Hartnoll of Stanford University gives his talk.

"Theories of bad metals"

Bad metals conduct electricity, but their conductivity is so small that they are seemingly incompatible with a conventional weakly interacting description. Controlled theoretical descriptions of bad metals are few and far between. I will discuss several different recent theories of bad metals that draw on ideas from hydrodynamics, the idea of fundamental bounds on quantum dynamics, and on the dynamics of spontaneously broken spacetimes symmetries (density waves).

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04/24/2017 - 2:10pm
 
"The Future of Space Launch – Beyond Chemical Rockets"

"The Future of Space Launch – Beyond Chemical Rockets"

Date: 
Mon, 04/24/2017 - 4:15pm
Location: 
428 Pupin Hall

Laetitia & Richard Garriott de Cayeux

Garriott Enterprises

"The Future of Space Launch – Beyond Chemical Rockets"

Since the dawn of the space race, space launch technology has relied on chemical combustion to send rockets into space, but if we want to dramatically reduce the cost of space access, we need new innovative technologies that go beyond the inherent limit of chemical combustion. One promising solution uses beamed energy to launch spaceplanes into orbit. Join space technology entrepreneur Laetitia Garriott de Cayeux and astronaut Richard Garriott de Cayeux as they discuss the current state of space launch technology and the physics behind the innovative ideas that are rapidly reducing the cost of space access.

 

About the speakers

Richard Lord British Garriott de Cayeux authored the famed Ultima series and is credited with creating the category of massively multiplayer games. A principal shaper of commercial spaceflight, he co-founded Space Adventures, the only company to arrange spaceflights for private citizens, and was the sixth private astronaut to live aboard the International Space Station. Laetitia Garriott de Cayeux is co-founder, President, and COO of Escape Dynamics, which is developing an electromagnetic externally-powered space launch system to send single-stage reusable rockets into LEO. Prior to this, she had a successful 15 year career in finance with Goldman Sachs, Renaissance Technologies, and then her own investment firm.

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04/24/2017 - 4:15pm
 
 
"Initial results from ASTROSAT, Multi-Wavelength near-Earth X-ray space observatory"

"Initial results from ASTROSAT, Multi-Wavelength near-Earth X-ray space observatory"

Date: 
Wed, 04/26/2017 - 1:00pm
Location: 
705 Pupin Hall

Please join us Wednesday, April 26, 2017, as P. Sreekumar, Director of Indian Institute of Astrophysics, Bangalore, give us his talk:

"Initial results from ASTROSAT, Multi-Wavelength near-Earth X-ray space observatory"

After more than a decade of planning and development, ASTROSAT was launched from India's east coast in Sept 2015. It is the first dedicated multiwavelength astronomy satellite from India and it carries 5 major payloads covering the UV to hard X-ray band. The Canadian Space Agency and Univ. of Leicester are collaborating on two of the payloads. After the initial phase of performance verification, the observatory was opened Oct 2016 for proposal-driven observations. The opportunity for international proposers begins from October 1 2017. ASTRONAUT has five instruments on board covering the visible (320–530 nm), near UV (180–300 nm), far UV (130–180 nm), soft X-ray (0.3–8 keV and 2–10 keV) and hard X-ray (3–80 keV and 10–150 keV) energy bands. I will briefly summarise the status of the observatory and discuss some of the new findings from ASTROSAT.

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04/26/2017 - 1:00pm
 
 
"Photon Processing via Four-Wave Mixing"
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04/28/2017 - 11:00am
 
 
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