# Events

#### Pheno & Vino Seminar, Rouven Essig, Stony Brook, "New Direct-Detection Probes of sub-GeV Dark Matter"

##### Sep 27, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303

Dark matter with MeV-to-GeV masses is a theoretically and phenomenologically interesting possibility. In this talk, I will describe how direct-detection experiments can probe this largely unexplored mass range. A particularly promising possibility is that dark matter scatters off electrons, causing ionization or excitation of atoms in a detector target material, which can lead to events containing one or more electrons or photons. I will review how existing XENON10 data probes dark matter with masses as low as a few MeV, and present an improved constraint using recent XENON100 data. After reviewing the challenges for xenon-based experiments to make further progress, I will discuss how experiments with different materials could significantly improve the sensitivity. This includes upcoming experiments using semiconductors (e.g. SuperCDMS, DAMIC) as well as new dedicated experiments using scintillators and other materials. I will focus on ideas that could be realized within the next five years, but also mention other efforts. I will also present a few simple sub-GeV dark matter models, which provide concrete experimental targets, and contrast direct-detection probes with searches at colliders and fixed-target experiments.

#### Math Physics Seminar, Eliran Subag, Weizmann, "Critical points and the Gibbs measure of a spherical spin glass model"

##### Sep 27, 2016 · 4:30 p.m.– 5:30 p.m. · Jadwin 343

For integers N let H_N(x) be an isotropic Gaussian field on the N-dimensional unit sphere, meaning that Cov(H_N(x),H_N(y)) is a function, f_N, of the inner product of <x,y>. The spherical spin glass models of statistical mechanics are such random fields, with f_N = N f with the function independent of the dimension N. The intricate landscape of the graph of H_N(x) may be studies through its critical points and the corresponding values. Focusing on the pure p-spin models, I will review recent developments concerning the distribution of the number of critical values at a given height and the associated extremal point process. Combining these results with a local investigation of the behaviour of H_N(x) in neighborhoods around the critical points, we obtain a detailed geometric picture for the Gibbs measure at low enough temperature. The measure concentrates on spherical "bands" around the deepest critical points. The main focus of the talk will be on the structure of such states, and its consequences. The talk is based on a joint work with Ofer Zeitouni.

#### Special Condensed Matter Seminar, Adam Nahum, MIT, "Quantum entanglement growth under random unitary dynamics"

##### Sep 29, 2016 · 2:00 p.m.– 3:30 p.m. · PCTS Seminar Room

A quantum many-body system, prepared initially in a state with low entanglement, will entangle distant regions dynamically. How does this happen? I will discuss entanglement entropy growth for quantum systems subject to random unitary dynamics — i.e. Hamiltonian evolution with time-dependent noise, or a random quantum circuit. I will show how entanglement growth in this ‘noisy’ situation exhibits remarkable universal structure, which in 1D is related to the Kardar—Parisi—Zhang equation. I will argue that understanding this structure leads us to heuristic pictures for entanglement growth which may be useful for more general (non-noisy) dynamics.

#### Hamilton Colloquium Series: Frans Pretorius, Princeton; "The Dynamical Strong-field Regime of General Relativity"

##### Sep 29, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10

In this talk I will describe the recent detection of gravitational waves by the LIGO/Virgo collaboration. The main event heard, GW150914, is consistent with the emission of gravitational waves from the late inspiral, merger and ringdown of two heavy stellar mass black holes. Many aspects of this event are fortuitous and remarkable, and I will discuss what it has taught us about strong-field gravity, binary black hole populations in the universe, and what it implies we can further learn over the next few years once LIGO is upgraded to design sensitivity.

#### Gravity Group Seminar, Mark Kamionkowski (JHU), "Dust polarization and interstellar turbulence"

##### Sep 30, 2016 · 12:00 p.m.– 1:30 p.m. · Joseph Henry Room

Perhaps the most surprising result from the Planck satellite is the observation that the E-mode power in the dust polarization is twice that in the B mode, in stark contrast to pre-Planck expectations of roughly equal dust powers in E and B modes.

I will show how the E- and B-mode powers are determined by fluctuations in the magnetized interstellar medium, the slow, fast, and Alfv\'en magnetohydrodynamic (MHD) waves. I will argue that the observed E/B ratio, as well as the TE (temperature-polarization) cross-correlation (which is observed to be positive) are not easily reconciled with expectations for the spectrum of fluctuations expected in the models of MHD turbulence usually invoked to account for the fluctuations. I will then discuss some alternative explanations (including the possibility that the scales probed by Planck overlap the outer scale for interstellar turbulence) for the dust-emission patterns seen in the Planck temperature-polarization maps.

I will then outline some interesting directions for future related research.

#### Condensed Matter Seminar, Chandra Varma, UCR, "Quantum Critical Fluctuations Leading to Strange Metals and Superconductors in 2D Metallic ..."

##### Oct 3, 2016 · 1:15 p.m.– 2:30 p.m. · PCTS Seminar Room

Models for metallic anti-ferromagnets map to the dissipative XY model as do XY ferromagnets, the superconductor-insulator transition, and the model forloop-current order in Cuprates. The spectral function of the quantum-critical fuctuations for this model in 2D for a range of parameters is determined by

topological defects - instantons and 2D vortices; it is a separable function of space and time, with a 1= dependence at criticality. The marginal fermi-liquid properties for the fermions follow from coupling to such fluctuations.

These fluctuations are directly measured by inelastic neutron scattering in the quantum-critical region of the new Fe- based compounds, in a 2D ferromagnet and in heavy-Fermions, and deduced in cuprates through analysis of ARPES. ARPES also reveals the coupling function of the fermions to the fluctuations so as to give nearly angle-independent normal self-energy but d-wave pairing energy.

#### HET Seminar | Dalimil Mazac | University of Waterloo | TBA

##### Oct 3, 2016 · 2:30 p.m.– 3:30 p.m. · PCTS Seminar Room

#### Pheno & Vino Seminar, Masha Baryakhtar, Perimeter, "TBA"

##### Oct 4, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303

Abstract: TBA

#### Hamilton Colloquium Series: Rana Adhikari, Caltech; "The truth behind the LIGO discoveries"

##### Oct 6, 2016 · 4:30 p.m.– 6:00 p.m. · Jadwin A10

After 50 years, the gravitational radiation community announced the detection of a binary black hole merger. The radiation traveled through space for a billion years and registered in the LIGO interferometers on Sep. 14. I will describe what really went on in the few years before the detection, what the prospect is for getting daily black hole signals, and what the fundamental quantum information limit for spacetime curvature estimation is.

#### Biophysics Seminar speaker Daniel Fisher, Stanford

##### Oct 10, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room

“Evolutionary Dynamics in High Dimensions”

#### Condensed Matter Seminar, Nuh Gedik, MIT, "Optical manipulation of electronic bands using Floquet-Bloch States"

##### Oct 10, 2016 · 1:15 p.m.– 2:30 p.m. · PCTS Seminar Room

The coherent optical manipulation of solids is emerging as a promising way to engineer novel quantum states of matter. The strong time-periodic potential of intense laser light was predicted to generate hybrid photon–electron states named Floquet–Bloch states. In this talk, I will report on first experimental observation of these states in topological insulators (TI). Using time- and angle-resolved photoemission spectroscopy, we show that an intense ultrashort mid-infrared pulse with energy below the bulk band gap of TI hybridizes with the surface Dirac fermions of a topological insulator to form Floquet-Bloch bands. The photon-dressed surface band structure is composed of a manifold of Dirac cones evenly spaced by the photon energy and exhibits polarization-dependent band gaps at the avoided crossings of the Dirac cones. Circularly polarized photons induce an additional gap at the Dirac point, which is a signature of broken time-reversal symmetry on the surface. Beyond topological insulators, manipulation of electronic bands via light matter interaction holds great promise in many other systems as well. I will illustrate this with our recent measurements on monolayer semiconducting transition-metal dichalcogenides in which we were able to break valley degeneracy using off-resonant circularly polarized light

#### HET Seminar | Oliver DeWolfe | University of Colorado | TBA

##### Oct 10, 2016 · 2:30 p.m.– 3:30 p.m. · PCTS Seminar Room

#### Lena Funcke, Max Planck Institute for Physics and Ludwig Maximilian University of Munich - “Rethinking the Origin of Small Neutrino Masses”

##### Oct 11, 2016 · 1:30 p.m.– 3:00 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study

The observed small neutrino masses are one of the greatest mysteries in current theoretical particle physics. Many possible origins have been proposed so far, such as the see-saw mechanism, radiative corrections, or large extra dimensions. While all these models have been connected in some way to the Higgs condensate, we propose a substantially different mechanism based on nonperturbative gravity: assuming that gravity contains a topological theta-term analogous to the famous theta-term of QCD, we show that a neutrino condensate emerges and effectively generates the small neutrino masses. This neutrino mass generation mechanism implies numerous phenomenological consequences, such as the invalidity of the cosmological neutrino mass bound, enhanced neutrino-neutrino interactions, and neutrino decays.

#### Pheno & Vino Seminar, Kohsaku Tobioka, Tel Aviv, U., "TBA"

##### Oct 11, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303

Abstract: TBA

#### Special Math Physics Seminar, Alessandro Giuliani, U. of Rome 3, "Universality of transport coefficients in the Haldane-Hubbard model"

##### Oct 12, 2016 · 4:30 p.m.– 5:30 p.m. · Jadwin 343

In this talk I will review some selected aspects of the theory of interacting electrons on the honeycomb lattice, with special emphasis on the Haldane-Hubbard model: this is a model for interacting electrons on the hexagonal lattice, in the presence of nearest and next-to-nearest neighbor hopping, as well as of a transverse dipolar magnetic field. I will discuss the key properties of its phase diagram, most notably the phase transition from a standard insulating phase to a Chern insulator, across a critical line, where the system exhibits semi-metallic behavior. I will also review the universality of its transport coefficients, including the quantization of the transverse conductivity within the gapped phases, and that of the longitudinal conductivity on the critical line. The methods of proof combine constructive Renormalization Group methods with the use of Ward Identities and the Schwinger-Dyson equation. Based on joint works with Vieri Mastropietro, Marcello Porta, Ian Jauslin.

#### Spec. Pheno & Vino, Oren Slone, Tel Aviv U.. "TBA"

##### Oct 13, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303

Abstract: TBA

#### Hamilton Colloquium Series: Markus Greiner, Harvard; Title TBA

##### Oct 13, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin A10

Abstract: to be announced

#### Biophysics Seminar speaker Anton Zilman, U. Toronto

##### Oct 17, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room

"Nuclear Pore Complex: Simple Physics of a Complex Biomachine"

#### CM Video Seminar, Andy Lucas, Harvard, "TBA"

##### Oct 17, 2016 · 1:15 p.m.– 2:30 p.m. · 87 Prospect

Abstract: TBA

#### Special Math Physics Seminar, Anna Vershynina, Basque Center, Spain, "Quantum analogues of geometric inequalities for Information theory"

##### Oct 17, 2016 · 4:30 p.m.– 5:30 p.m. · Jadwin 343

Geometric inequalities, such as entropy power inequality or the isoperimetric inequality, relate geometric quantities, such as volumes and surface areas. Classically, these inequalities have useful applications for obtaining bounds on channel capacities, and deriving log-Sobolev inequalities. In my talk I provide quantum analogues of certain well-known inequalities from classical Information Theory, with the most notable being the isoperimetric inequality for entropies. The latter inequality is useful for the study of convergence of certain semigroups to fixed points. In the talk I demonstrate how to apply the isoperimetric inequality for entropies to show exponentially fast convergence of quantum Ornstein-Uhlenbeck (qOU) semigroup to a fixed point of the process. The inequality representing the fast convergence can be viewed as a quantum analogue of a classical Log-Sobolev inequality. As a separate result, necessary for the fast convergence of qOU semigroup, I argue that gaussian thermal states minimize output entropy for the attenuator semigroup among all states with a given mean-photon number.

#### Math Physics Seminar, Vieri Mastropietro, U. of Milano, "Localization of interacting fermions with quasi-random disorder"

##### Oct 18, 2016 · 4:30 p.m.– 5:30 p.m. · Jadwin 343

We consider interacting electrons in a one dimensional lattice with an incommensurate Aubry-Andre' potential in the regime when the single-particle eigenstates are localized. We rigorously establish persistence of ground state localization in presence of weak many-body interaction.The proof uses a quantum many body extension of methods adopted for the stability of tori of nearly integrable hamiltonian systems, and relies on number-theoretic properties (Diophantine conditions) of the potential incommensurate frequency and phase.

#### Hamilton Colloquium Series: Stephen Shenker, Stanford; "Quantum gravity and quantum chaos"

##### Oct 20, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin A10

Abstract: TBA

#### Biophysics Seminar speaker Robert Gütig, Max Planck

##### Oct 24, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room

“Spiking neurons can discover predictive features by aggregate-label learning”

#### HET Seminar | Alba Grassi | ICTP in Trieste | TBA

##### Oct 24, 2016 · 2:30 p.m.– 6:00 p.m. · PCTS Seminar Room

#### Pheno & Vino Seminar, David Shih, Rutgers, "TBA"

##### Oct 25, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303

Abstract: TBA

#### Math Physics Seminar, Eviatar Procaccia, Texas A & M, "Can one hear the shape of a random walk?"

##### Oct 25, 2016 · 4:30 p.m.– 5:30 p.m. · Jadwin 343

We consider a Gibbs distribution over random walk paths on the square lattice, proportional to a random weight of the path’s boundary . We show that in the zero temperature limit, the paths condensate around an asymptotic shape. This limit shape is characterized as the minimizer of the functional, mapping open connected subsets of the plane to the sum of their principle eigenvalue and perimeter (with respect to the first passage percolation norm). A prime novel feature of this limit shape is that it is not in the class of Wulff shapes.

Joint work with Marek Biskup

#### Hamilton Colloquium Series: David Vanderbilt, Rutgers University; Title: TBA

##### Oct 27, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin A10

Abstract: TBA

#### Biophysics Seminar speaker Lisa Manning, Syracuse U.

##### Nov 7, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room

"Jamming and glassy dynamics in biological tissues".

#### CM Video Seminar, Andy Mackenzie, Max Planck, "TBA"

##### Nov 7, 2016 · 1:15 p.m.– 2:30 p.m. · PCTS Seminar Room

Abstract: TBA

#### HET Seminar | Daniel Park | Rutgers University | TBA

##### Nov 7, 2016 · 2:30 p.m.– 4:00 p.m. · PCTS Seminar Room

#### Pheno & Vino Seminar, Gordon Krnjaic, Perimeter, "TBA"

##### Nov 8, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303

Abstract: TBA

#### Hamilton Colloquium Series: Neal Weiner, NYU; Title: TBA

##### Nov 10, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin A10

Abstract: TBA

#### HET Seminar | Thomas Mertens | Princeton University | “TBA”

##### Nov 11, 2016 · 1:45 p.m.– 3:00 p.m. · Jadwin A06

#### CM Video Seminar, Brian Swingle, Harvard, "TBA"

##### Nov 14, 2016 · 1:15 p.m.– 2:30 p.m. · Jadwin 111

Abstract: TBA

#### Senthil Todadri, Massachusetts Institute of Technology - "TBA"

##### Nov 14, 2016 · 2:30 p.m.– 4:00 p.m. · Bloomberg Lecture Hall - Institute for Advanced Study

#### Biophysics Seminar speaker Ido Golding, Baylor College of Medicine

##### Nov 21, 2016 · 12:30 p.m.– 1:00 p.m. · Joseph Henry Room

"Deciphering the stochastic kinetics of gene regulation".

#### Condensed Matter Seminar, Andrea Liu, U. Penn, "TBA"

##### Nov 21, 2016 · 1:15 p.m.– 2:30 p.m. · PCTS Seminar Room

Abstract: TBA

#### HET Seminar | Bogdan Stoica | Brandeis University | TBA

##### Nov 21, 2016 · 2:30 p.m.– 6:00 p.m. · PCTS Seminar Room

#### Biophysics Seminar speaker Eric Siggia, Rockefeller U.

##### Nov 28, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room

“Evolution as prediction: temperature compensated circadian clocks and how to change a fly into a mosquito”

#### Pheno & Vino Seminar, Francis-Yan Cyr-Racine, Harvard, "TBA"

##### Nov 29, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303

Abstract: TBA

#### Biophysics Seminar speaker Vernita Gordon, UT Austin

##### Dec 5, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room

“Soft-matter mechanics in the initiation and robustness of bacterial biofilms.”

#### HET Seminar | Andreas Karch | U. of Washington | TBA

##### Dec 5, 2016 · 2:30 p.m.– 6:00 p.m. · Jadwin A06

#### Pheno & Vino Seminar, Eder Izaguirre, Perimeter, "TBA"

##### Dec 6, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin 303

Abstract: TBA

#### Biophysics Seminar speaker David Williams, Rochester

##### Dec 12, 2016 · 12:00 p.m.– 1:00 p.m. · Joseph Henry Room

“Seeing through the Retina.”

#### Anton Kapustin, California Institute of Technology - "TBA"

##### Dec 12, 2016 · 2:30 p.m.– 4:00 p.m. · 87 Prospect

#### Hamilton Colloquium Series: Christopher Monroe, University of Maryland; Title: TBA

##### Dec 15, 2016 · 4:00 p.m.– 5:30 p.m. · Jadwin A10

Abstract: TBA

#### Spec. Condensed Matter Seminar, Yakir Aharonov, Tel Aviv U. " TBA"

##### Feb 22, 2017 · 2:00 p.m.– 3:30 p.m. · PCTS Seminar Room

Abstract: TBA

#### 2017 Conference for Undergradute Women in Physics

##### Sep 29, 2017 · 4:30 p.m.– 6:00 p.m. · McDonnell A02

What: Apply now for the 2017 Conference for Undergraduate Women in Physics

When: Oct. 14 deadline for the Jan. 13 to 15 conference

Where: Princeton University

Cost: The conference,lodging and meals are covered. Students pay $45 registration fee and transportation.

Applications and more information: cuwip@princeton.edu or contact Shannon Swilley Greco, sgreco@pppl.gov, 609-243-2208