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Publications

Lifshitz transition from valence fluctuations in YbAl3

Cornell Affiliated Author(s)
Author
S. Chatterjee
J.P. Ruf
H.I. Wei
K.D. Finkelstein
D.G. Schlom
K.M. Shen
Abstract

In mixed-valent Kondo lattice systems, such as YbAl3, interactions between localized and delocalized electrons can lead to fluctuations between two different valence configurations with changing temperature or pressure. The impact of this change on the momentum-space electronic structure is essential for understanding their emergent properties, but has remained enigmatic.

Journal
Nature Communications
Date Published
Funding Source
DMR-1120296
0335765
0847385
0903653
1120296
1144153
1332208
DGE-0903653
DGE-1144153
DMR-0847385
DMR-1332208
FA2386-12-1-3013
GBMF3850
2002S
Group (Lab)
Kyle Shen Group

Mechanical properties and structure-function relationships of human chondrocyte-seeded cartilage constructs after in vitro culture

Cornell Affiliated Author(s)
Author
J.M. Middendorf
D.J. Griffin
S. Shortkroff
C. Dugopolski
S. Kennedy
J. Siemiatkoski
Itai Cohen
L.J. Bonassar
Abstract

Autologous Chondrocyte Implantation (ACI) is a widely recognized method for the repair of focal cartilage defects. Despite the accepted use, problems with this technique still exist, including graft hypertrophy, damage to surrounding tissue by sutures, uneven cell distribution, and delamination. Modified ACI techniques overcome these challenges by seeding autologous chondrocytes onto a 3D scaffold and securing the graft into the defect.

Journal
Journal of Orthopaedic Research
Date Published
Funding Source
1536463
DGE-1650441
1120296
1144153
DMR-1120296
Research Area
Group (Lab)
Itai Cohen Group

Review of pseudogaps in strongly interacting Fermi gases

Cornell Affiliated Author(s)
Author
E.J. Mueller
Abstract

A central challenge in modern condensed matter physics is developing the tools for understanding nontrivial yet unordered states of matter. One important idea to emerge in this context is that of a 'pseudogap': the fact that under appropriate circumstances the normal state displays a suppression of the single particle spectral density near the Fermi level, reminiscent of the gaps seen in ordered states of matter. While these concepts arose in a solid state context, they are now being explored in cold gases.

Journal
Reports on Progress in Physics
Date Published
Funding Source
1508300

Determining Quiescent Colloidal Suspension Viscosities Using the Green-Kubo Relation and Image-Based Stress Measurements

Cornell Affiliated Author(s)
Author
N.Y.C. Lin
M.K. Bierbaum
Itai Cohen
Abstract

By combining confocal microscopy and stress assessment from local structural anisotropy, we directly measure stresses in 3D quiescent colloidal liquids. Our noninvasive and nonperturbative method allows us to measure forces 50 fN with a small and tunable probing volume, enabling us to resolve the stress fluctuations arising from particle thermal motions. We use the Green-Kubo relation to relate these measured stress fluctuations to the bulk Brownian viscosity at different volume fractions, comparing against simulations and conventional rheometry measurements.

Journal
Physical Review Letters
Date Published
Funding Source
1509308
DMR-1507607
DOE-DE-FG02-07ER46393
Group (Lab)
Itai Cohen Group

Lattice Homotopy Constraints on Phases of Quantum Magnets

Cornell Affiliated Author(s)
Author
Hoi Po
Haruki Watanabe
Chao-Ming Jian
Michael Zaletel
Abstract

The Lieb-Schultz-Mattis (LSM) theorem and its extensions forbid trivial phases from arising in certain quantum magnets. Constraining infrared behavior with the ultraviolet data encoded in the microscopic lattice of spins, these theorems tie the absence of spontaneous symmetry breaking to the emergence of exotic phases like quantum spin liquids.

Journal
Physical Review Letters
Date Published
Funding Source
17K17678
Group (Lab)
Chao-Ming Jian Group

Quantum butterfly effect in weakly interacting diffusive metals

Cornell Affiliated Author(s)
Author
A.A. Patel
Debanjan Chowdhury
S. Sachdev
B. Swingle
Abstract

We study scrambling, an avatar of chaos, in a weakly interacting metal in the presence of random potential disorder. It is well known that charge and heat spread via diffusion in such an interacting disordered metal. In contrast, we show within perturbation theory that chaos spreads in a ballistic fashion. The squared anticommutator of the electron-field operators inherits a light-cone-like growth, arising from an interplay of a growth (Lyapunov) exponent that scales as the inelastic electron scattering rate and a diffusive piece due to the presence of disorder.

Journal
Physical Review X
Date Published
Funding Source
1360789
Group (Lab)
Debanjan Chowdhury Group

Model for continuous thermal metal to insulator transition

Cornell Affiliated Author(s)
Author
Chao-Ming Jian
Zhen Bi
Cenke Xu
Abstract

We propose a d-dimensional interacting Majorana fermion model with quenched disorder, which gives us a continuous quantum phase transition between a diffusive thermal metal phase with a finite entropy density to an insulator phase with zero entropy density. This model is based on coupled Sachdev-Ye-Kitaev model clusters, and hence has a controlled large-N limit. The metal-insulator transition is accompanied by a spontaneous time-reversal symmetry breaking.

Journal
Physical Review B
Date Published
Funding Source
1151208
Group (Lab)
Chao-Ming Jian Group

Onset of many-body chaos in the O (N) model

Cornell Affiliated Author(s)
Author
Debanjan Chowdhury
B. Swingle
Abstract

The growth of commutators of initially commuting local operators diagnoses the onset of chaos in quantum many-body systems. We compute such commutators of local field operators with N components in the (2+1)-dimensional O(N) nonlinear sigma model to leading order in 1/N. The system is taken to be in thermal equilibrium at a temperature T above the zero temperature quantum critical point separating the symmetry broken and unbroken phases. The commutator grows exponentially in time with a rate denoted λL.

Journal
Physical Review D
Date Published
Funding Source
GBMF-4303
W911NF-14-1-0003
Group (Lab)
Debanjan Chowdhury Group

Erratum: Broken rotational symmetry on the Fermi surface of a high-Tc superconductor (npj Quantum Materials (2017) DOI: 10.1038/s41535-017-0013-z)

Cornell Affiliated Author(s)
Author
B.J. Ramshaw
N. Harrison
S.E. Sebastian
S. Ghannadzadeh
K.A. Modic
D.A. Bonn
W.N. Hardy
R. Liang
P.A. Goddard
Abstract

The original version of this Article contained the following errors in the legend of Figure 3, where: "The right hand panels are projections of this surface into the ka-kb plane," Now reads: "b-e are projections of this surface into the ka-kb plane," In addition, "The upper two panels involve two anisotropic CDWs, with Q2 = (δ,0,1/2)" Now reads: "The upper two panels involve two anisotropic CDWs, with Q1 = (δ,0,1/2) In addition, "followed by uni-axial CDW reconstruction with Q2 = (δ,0,0)," Now reads: "followed by uni-axial CDW reconstruction with Q = (δ,0,0)," In addition, "The simplest

Journal
npj Quantum Materials
Date Published
Group (Lab)
Brad Ramshaw Group

Controlling the alignment of rodlike colloidal particles with time-dependent shear flows

Cornell Affiliated Author(s)
Author
B.D. Leahy
D.L. Koch
Itai Cohen
Abstract

While colloidal suspensions of nonspherical particles have been studied for decades, most work has focused on describing their behavior in flows with simple time behavior. Little is known about their behavior in flows with complex variations in time, and in particular, the possibility of varying the flow to control the suspension's properties. Here, we take advantage of a recent solution for the orientation dynamics of a dilute suspension under an arbitrary periodic, high-frequency shear flow to control particle alignment and suspension rheology.

Journal
Journal of Rheology
Date Published
Funding Source
1232666
1435013
1509308
CBET-PMP-1435013
Group (Lab)
Itai Cohen Group