Latest Publications
• 14 Sep 2021 Preprint arXiv

## Degeneracy-projected polarization formulas for Hall-type conductivities

Abstract
Kubo formulas for Hall, transverse thermoelectric and thermal Hall conductivities are simplified into on-shell commutators of degeneracy projected polarizations. The new expressions are computationally economical, and apply to general Hamiltonians without a gap restriction. We show that Hall currents in open boundaries are carried by gapless chiral excitations. Extrapolation… show more
• 6 Sep 2021 Journal Article Nature Communications

## Electronic Floquet gyro-liquid crystal

Iliya Esin, Gaurav Kumar Gupta, Erez Berg, Mark S Rudner, Netanel H Lindner
Abstract
Floquet engineering uses coherent time-periodic drives to realize designer band structures on-demand, thus yielding a versatile approach for inducing a wide range of exotic quantum many-body phenomena. Here we show how this approach can be used to induce non-equilibrium correlated states with spontaneously broken symmetry in lightly doped semiconductors. In the presence… show more
• 30 Aug 2021 Journal Article SciPost Physics

## Rank $Q$ E-String on Spheres with Flux

Chiung Hwang, Shlomo S Razamat, Evyatar Sabag, Matteo Sacchi
Abstract
We consider compactifications of rank $Q$ E-string theory on a genus zero surface with no punctures but with flux for various subgroups of the $\text{E}_8\times \text{SU}(2)$ global symmetry group of the six dimensional theory. We first construct a simple Wess-Zumino model in four dimensions corresponding to the compactification on a sphere with one puncture and a… show more
• 16 Aug 2021 Journal Article Physical Review E

## Real-space origin of topological band gaps, localization, and reentrant phase transitions in gyroscopic metamaterials

Noah P Mitchell, Ari M Turner, William T M Irvine
Abstract
Lattices of interacting gyroscopes naturally support band gaps and topologically protected wave transport along material boundaries. Recently the authors and their collaborators found that amorphous arrangements of such coupled gyroscopes also support nontrivial topological phases. In contrast to periodic systems, for which there is a comprehensive understanding and… show more
• 12 Aug 2021 Preprint arXiv

## Quantum tomography of entangled spin-multi-photon states

Abstract
We present a novel method for quantum tomography of multi-qubit states. We apply the method to spin-multi-photon states, which we produce by periodic excitation of a semiconductor quantum-dot- confined spin every 1/4 of its coherent precession period. These timed excitations lead to the deterministic generation of strings of entangled photons in a cluster state. We show… show more
• 7 Aug 2021 Journal Article Current Opinion in Cell Biology

## Cytoskeletal symmetry breaking in animal cells

Abstract

Symmetry breaking is a crucial step in structure formation and function of all cells, necessary for cell movement, cell division, and polarity establishment. Although the mechanisms of symmetry breaking are diverse, they often share common characteristics. Here we review examples of nematic, polar, and chiral cytoskeletal symmetry breaking in animal cells, and analogous

• 5 Aug 2021 Journal Article Physical Review E

## Extinctions of coupled populations, and rare event dynamics under non-Gaussian noise

Abstract
The survival of natural populations may be greatly affected by environmental conditions that vary in space and time. We look at a population residing in two locations (patches) coupled by migration, in which the local conditions fluctuate in time. We report on two findings. First, we find that, unlike rare events in many other systems, here the histories leading to a… show more
• 2 Aug 2021 Preprint arXiv

## The PG-RQS survey. Building the radio spectral distribution of radio-quiet quasars. I. The 45-GHz data

Ranieri D Baldi, Ari Laor, Ehud Behar, Assaf Horesh, Francesca Panessa, Ian M McHardy, Amy Kimball
Abstract
The origin of the radio emission in radio-quiet quasars (RQQs) remains unclear. Radio photons may be produced by a scaled-down version of the relativistic jets observed in radio-loud (RL) AGN, an AGN-driven wind, the accretion disc corona, AGN photon-ionisation of ambient gas (free-free emission), or star formation (SF). Here, we report a pilot study, part of a radio… show more
• Aug 2021 Journal Article Journal of Statistical Mechanics: Theory and Experiment

## Exact fluctuating hydrodynamics of active lattice gases -- Typical fluctuations

Tal Agranov, Sunghan Ro, Yariv Kafri, Vivien Lecomte
Abstract
We extend recent results on the exact hydrodynamics of a system of diffusive active particles displaying a motility-induced phase separation to account for typical fluctuations of the dynamical fields. By calculating correlation functions exactly in the homogeneous phase, we find that two macroscopic length scales develop in the system. The first is related to the… show more
• 12 Jul 2021 Journal Article Physical Review Letters

## Random Close Packing as a Dynamical Phase Transition

Sam Wilken, Rodrigo Guerra, Dov Levine, Paul Chaikin
Abstract
Sphere packing is an ancient problem. The densest packing is known to be a face-centered cubic (FCC) crystal, with space-filling fraction ϕ_{FCC}=π/sqrt[18]≈0.74. The densest "random packing," random close packing (RCP), is yet ill defined, although many experiments and simulations agree on a value ϕ_{RCP}≈0.64. We introduce a simple absorbing-state model, biased random… show more
• 7 Jul 2021 Journal Article Physical Review Letters

## Measurement of the Static Structure Factor in a Paraxial Fluid of Light Using Bragg-like Spectroscopy

Clara Piekarski, Wei Liu, Jeff Steinhauer, Elisabeth Giacobino, Alberto Bramati, Quentin Glorieux
Abstract
We implement Bragg-like spectroscopy in a paraxial fluid of light by imprinting analogues of short Bragg pulses on the photon fluid using wavefront shaping with a spatial light modulator. We report a measurement of the static structure factor, $S(k)$, and we find a quantitative agreement with the prediction of the Feynman relation revealing indirectly the presence of… show more
• Jul 2021 Journal Article Journal of Geometry and Physics

## Relating diffraction and spectral data of aperiodic tilings: Towards a Bloch theorem

Abstract
The purpose of this paper is to show the relationship in all dimensions between the structural (diffraction pattern) aspect of tilings (described by Čech cohomology of the tiling space) and the spectral properties (of Hamiltonians defined on such tilings) defined by K-theory, and to show their equivalence in dimensions ≤ 3. A theorem makes precise the conditions for… show more
• 22 Jun 2021 Journal Article Monthly Notices of the Royal Astronomical Society

## Probing supermassive stars and massive black hole seeds through gravitational wave inspirals

Abstract
We propose a novel source of gravitational wave emission: the inspirals of compact fragments inside primordial supermassive stars (SMSs). Such systems are thought to be an essential channel in the as-yet little understood formation of supermassive black holes (SMBHs). One model suggests that high accretion rates of $0.1$-1 M$_\odot$/yr attainable in atomically-cooled… show more
• 2 Jun 2021 Journal Article Applied Physics Letters

## Circularly polarized high harmonic generation through virtual circular birefringence

Liran Hareli, Gavriel Lerner, Oren Cohen, Alon Bahabad
Abstract
We suggest a macroscopic scheme for generating circularly polarized high harmonics. The scheme uses a superposition of circularly polarized pump beams with different spatial modes, realizing a perturbed linearly polarized field which rotates along the propagation axis due to virtual circular birefringence. This method provides a spectral selectivity for the harmonic… show more
• 25 May 2021 Journal Article Quantum Materials

## Critical charge fluctuations and emergent coherence in a strongly correlated excitonic insulator

Pavel A Volkov, Mai Ye, Himanshu Lohani, Irena Feldman, Amit Kanigel, Girsh Blumberg
Abstract
Excitonic insulator is a coherent electronic phase that results from the formation of a macroscopic population of bound particle-hole pairs - excitons. With only a few candidate materials known, the collective excitonic behavior is challenging to observe, being obscured by crystalline lattice effects. Here we use polarization-resolved Raman spectroscopy to reveal the… show more
• 15 Apr 2021 Preprint arXiv

## Periodic dynamics in superconductors induced by an impulsive optical quench

Pavel E Dolgirev, Alfred Zong, Marios H Michael, Jonathan B Curtis, Daniel K Podolsky, Andrea Cavalleri, Eugene Demler
Abstract
A number of experiments have evidenced signatures of enhanced superconducting correlations after photoexcitation. Initially, these experiments were interpreted as resulting from quasi-static changes in the Hamiltonian parameters, for example, due to lattice deformations or melting of competing phases. Yet, several recent observations indicate that these conjectures are… show more
• 1 Apr 2021 Journal Article Research Notes of the AAS

## The α ox–He ii EW Connection in Radio-loud Quasars

John D Timlin, Shifu Zhu, W N Brandt, Ari Laor
Abstract
Radio-loud quasars (RLQs) are known to produce excess X-ray emission, compared to radio-quiet quasars (RQQs) of the same luminosity, commonly attributed to jet-related emission. Recently, we found that the He ii EW and α ox in RQQs are strongly correlated, which suggests that their extreme-ultraviolet (EUV) and X-ray emission mechanisms are tightly related. Using 48… show more
• 18 Mar 2021 Conference Paper Bulletin of the American Physical Society

## Predictive capacity of a dynamical system

Kamesh Krishnamurthy, William S Bialek, Anna Frishman, Xiaowen Chen
Abstract
Organisms need to extract information about their environment and interact with it. To do this, their internal degrees of freedom(d.o.f), say N of them, must carry information about the environment. A large body of work has argued how the number (N) and structure of the internal d.o.f are “efficient” in representing the external information. Typically, this information… show more