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Publications

Fractionalization and Topology in Amorphous Electronic Solids

Cornell Affiliated Author(s)
Author
S. Kim
A. Agarwala
Debanjan Chowdhury
Abstract

Band topology is traditionally analyzed in terms of gauge-invariant observables associated with crystalline Bloch wave functions. Recent work has demonstrated that many of the free fermion topological characteristics survive even in an amorphous setting. In this Letter, we extend these studies to incorporate the effect of strong repulsive interactions on the fate of topology and other correlation induced phenomena.

Journal
Physical Review Letters
Date Published
Funding Source
IITK/PHY/2022010
Group (Lab)
Debanjan Chowdhury Group

Supercooling of the A phase of 3He

Author
Y. Tian
D. Lotnyk
A. Eyal
K. Zhang
N. Zhelev
T.S. Abhilash
A. Chavez
E.N. Smith
M. Hindmarsh
J. Saunders
E. Mueller
J.M. Parpia
Abstract

Because of the extreme purity, lack of disorder, and complex order parameter, the first-order superfluid 3He A–B transition is the leading model system for first order transitions in the early universe. Here we report on the path dependence of the supercooling of the A phase over a wide range of pressures below 29.3 bar at nearly zero magnetic field. The A phase can be cooled significantly below the thermodynamic A–B transition temperature.

Journal
Nature Communications
Date Published
Funding Source
DMR-2002692
NNCI-1542081
PHY-2110250
824109
EP/J022004/1
ST/T00682X/1
Group (Lab)
Jeevak Parpia Group

Intermediate-scale theory for electrons coupled to frustrated local moments

Cornell Affiliated Author(s)
Author
A.J. McRoberts
J.F. Méndez-Valderrama
R. Moessner
Debanjan Chowdhury
Abstract

A classic route for destroying long-lived electronic quasiparticles in a weakly interacting Fermi liquid is to couple them to other low-energy degrees of freedom that effectively act as a bath. We consider here the problem of electrons scattering off the spin fluctuations of a geometrically frustrated antiferromagnet, whose nonlinear Landau-Lifshitz dynamics, which remains nontrivial at all temperatures, we model in detail.

Journal
Physical Review B
Date Published
Funding Source
247310070
390858490
EXC 2147
SFB 1143
Group (Lab)
Debanjan Chowdhury Group

Determining biomolecular structures near room temperature using X-ray crystallography: Concepts, methods and future optimization

Cornell Affiliated Author(s)
Author
R.E. Thorne
Abstract

For roughly two decades, cryocrystallography has been the overwhelmingly dominant method for determining high-resolution biomolecular structures.

Journal
Acta Crystallographica Section D: Structural Biology
Date Published
Funding Source
DE-SC0019546
Group (Lab)
Robert Thorne Group

Material normal energy distribution for field emission analyses from monocrystalline surfaces

Cornell Affiliated Author(s)
Author
J.I. Mann
Y. Li
J.K. Nangoi
Tomas Arias
J.B. Rosenzweig
Abstract

Electron field emission is a complicated phenomenon which is sensitive not only to the particular material under illumination but also to the specific crystalline orientation of the surface. Summarizing the ability for a crystal to emit in a particular direction would be of great use when searching for good field emitters. In this paper we propose a material normal energy distribution which describes the ability of the bound electrons to tunnel under an intense electric field.

Conference Name
Journal of Physics Conference Series
Date Published
Funding Source
PHY-1549132
Group (Lab)
Tomas Arias Group

Rapid method for computing the mechanical resonances of irregular objects

Cornell Affiliated Author(s)
Author
Avi Shragai
Florian Theuss
Gael Grissonnanche
B. Ramshaw
Abstract

A solid object's geometry, density, and elastic moduli completely determine its spectrum of normal modes. Solving the inverse problem - determining a material's elastic moduli given a set of resonance frequencies and sample geometry - relies on the ability to compute resonance spectra accurately and efficiently. Established methods for calculating these spectra are either fast but limited to simple geometries, or are applicable to arbitrarily shaped samples at the cost of being prohibitively slow.

Journal
Journal of the Acoustical Society of America
Date Published
Group (Lab)
Brad Ramshaw Group

Introductory physics students' recognition of strong peers: Gender and racial or ethnic bias differ by course level and context

Cornell Affiliated Author(s)
Author
M. Sundstrom
A.B. Heim
B. Park
N.G. Holmes
Abstract

Researchers have pinpointed recognition from others as one of the most important dimensions of students' science and engineering identity. Studies, however, have found gender biases in students' recognition of their peers, with inconsistent patterns across introductory science and engineering courses. Toward finding the source of this variation, we examine whether a gender bias exists in students' nominations of strong peers across three different remote, introductory physics courses with varying student populations (varying demographics, majors, and course levels).

Journal
Physical Review Physics Education Research
Date Published
Funding Source
DGE-2139899
DUE-1836617
Group (Lab)
Natasha Holmes Group

Neuromuscular embodiment of feedback control elements in Drosophila flight

Cornell Affiliated Author(s)
Author
S.C. Whitehead
S. Leone
T. Lindsay
M.R. Meiselman
N.J. Cowan
M.H. Dickinson
N. Yapici
D.L. Stern
T. Shirangi
Itai Cohen
Abstract

While insects such as Drosophila are flying, aerodynamic instabilities require that they make millisecond time scale adjustments to their wing motion to stay aloft and on course. These stabilization reflexes can be modeled as a proportional-integral (PI) controller; however, it is unclear how such control might be instantiated in insects at the level of muscles and neurons.

Journal
Science Advances
Date Published
Funding Source
IOS 1452510
IOS 1546710
IOS 1845673
N00014-21-1-2431
R21AI149772
1R01NS116595
61651-EG
Research Area
Group (Lab)
Itai Cohen Group

Role of conservation laws in the density matrix renormalization group

Cornell Affiliated Author(s)
Author
T.G. Kiely
E.J. Mueller
Abstract

We explore matrix product state approximations to wave functions which have spontaneously broken symmetries or are critical. We are motivated by the fact that symmetries, and their associated conservation laws, lead to block-sparse matrix product states. Numerical calculations which take advantage of these symmetries run faster and require less memory. However, in symmetry-broken and critical phases the block-sparse ansatz yields less accurate energies. We characterize the role of conservation laws in matrix product states and determine when it is beneficial to make use of them.

Journal
Physical Review B
Date Published
Funding Source
PHY-2110250

Understanding interaction network formation across instructional contexts in remote physics courses

Cornell Affiliated Author(s)
Author
M. Sundstrom
A. Schang
A.B. Heim
N.G. Holmes
Abstract

Engaging in interactions with peers is important for student learning. Many studies have quantified patterns of student interactions in in-person physics courses using social network analysis, finding different network structures between instructional contexts (lecture and laboratory) and styles (active and traditional). Such studies also find inconsistent results as to whether and how student-level variables (e.g., grades and demographics) relate to the formation of interaction networks.

Journal
Physical Review Physics Education Research
Date Published
Funding Source
DGE-2139899
DUE-1836617