Conference

Displaying 2725 - 2736 of 4905

Early Universe phenomenology after BICEP

Matias Zaldarriaga Institute for Advanced Study (IAS) - School of Natural Sciences (SNS)

April 04, 2014

PIRSA:14040125
The Importance of Being Curved

Matthew Kleban New York University (NYU)

April 04, 2014

PIRSA:14040124
B modes for galaxy surveys

Marc Kamionkowski Johns Hopkins University - Department of Physics & Astronomy

April 04, 2014

PIRSA:14040123
Prospects for Future Measurements
- Douglas Scott University of British Columbia
- Mark Halpern University of British Columbia
- Barth Netterfield University of Toronto
- Rachel Bean Cornell University
- Matt Dobbs McGill University
April 04, 2014

PIRSA:14040122
Results from BICEP 2

Christopher Sheehy University of Chicago - Department of Physics

April 04, 2014

PIRSA:14040131
Overview

Kendrick Smith Perimeter Institute for Theoretical Physics

April 04, 2014

PIRSA:14040121
Many-body localization with dipoles

Chris Laumann Boston University

February 14, 2014

PIRSA:14020129
Low Spin State Mott Insulators and Emergence of novel Quantum Spin Liquids

Baskaran Ganapathy Institute of Mathematical Sciences

February 14, 2014

PIRSA:14020128
A unification of symmetric Z2 spin liquids on kagome lattice

Yuan-Ming Lu

February 14, 2014

PIRSA:14020118
How universal is the entanglement spectrum?

Anushya Chandran Perimeter Institute for Theoretical Physics

February 14, 2014

PIRSA:14020132
Are non-Fermi-liquids stable to pairing?

Max Metlitski Massachusetts Institute of Technology (MIT) - Department of Physics

February 13, 2014

PIRSA:14020143
Gauging symmetry of 2D topological phases

Zhenghan Wang Microsoft Corporation

February 13, 2014

PIRSA:14020125

Early Universe phenomenology after BICEP

Matias Zaldarriaga Institute for Advanced Study (IAS) - School of Natural Sciences (SNS)

April 04, 2014

PIRSA:14040125
The Importance of Being Curved

Matthew Kleban New York University (NYU)

April 04, 2014

PIRSA:14040124
B modes for galaxy surveys

Marc Kamionkowski Johns Hopkins University - Department of Physics & Astronomy

April 04, 2014

PIRSA:14040123
Prospects for Future Measurements
- Douglas Scott University of British Columbia
- Mark Halpern University of British Columbia
- Barth Netterfield University of Toronto
- Rachel Bean Cornell University
- Matt Dobbs McGill University
April 04, 2014

PIRSA:14040122
Results from BICEP 2

Christopher Sheehy University of Chicago - Department of Physics

April 04, 2014

PIRSA:14040131
Overview

Kendrick Smith Perimeter Institute for Theoretical Physics

April 04, 2014

PIRSA:14040121
Many-body localization with dipoles

Chris Laumann Boston University

February 14, 2014

PIRSA:14020129

Statistical mechanics is the framework that connects thermodynamics to the microscopic world. It hinges on the assumption of equilibration; when equilibration fails, so does much of our understanding. In isolated quantum systems, this breakdown is captured by the phenomenon known as many-body localization. This breakdown manifests in a variety of ways, as elucidated by much recent theoretical and numerical work. Many-body localized phases violate Ohm's law and Fourier's law as they conduct neither charge nor heat; they can exhibit symmetry breaking and/or topological orders in dimensions normally forbidden by Mermin-Wagner arguments; they hold potential as strongly interacting quantum computers due to the slow decay of local coherence.
In this talk, I will briefly introduce the basic phenomena of many-body localization and review its theoretical status. To date, none of these phenomena has been observed in an experimental system, in part because of the isolation required to avoid thermalization. I will consider several dipolar systems which we believe to be ideal platforms for the realization of MBL phases and for investigating the associated delocalization phase transition. The presence of strong interactions in these systems underlies their potential for exploring physics beyond that of single particle Anderson localization. However, the power law of the dipolar interaction immediately raises the question: can localization in real space persist in the presence of such long-range interactions?
I will review and extend several arguments producing criteria for localization in the presence of power laws and present small-scale numerics regarding the MBL transition in several of the proposed dipolar systems.
Associated preprint:
N. Yao, CRL, S. Gopalakrishnan, M. Knap, M. Mueller, E. Demler., M. Lukin arXiv:1311.7151
Low Spin State Mott Insulators and Emergence of novel Quantum Spin Liquids

Baskaran Ganapathy Institute of Mathematical Sciences

February 14, 2014

PIRSA:14020128

In a conventional Mott insulator, magnitude of local spin moments remain fixed. They are `fixed spin Mott insulators'. We suggest that, in a multi orbital Hubbard model, when local Hund coupling is won over by inter-orbital superexchange couplings between neighboring sites, local spin moment can decrease its value in a cooperative fashion, through a first order phase transition, These are `Low spin state Mott insulators' (LSSMI). The minimal value of spins that can be reached are zero (half), for even (odd) number of electrons per site, We show that in LSSMI, depending on orbital degeneracy and electron number per site, novel quantum spin liquids can emerge, We discuss systems such as Fe arsenide, Fe selenide family and La2CoO3 in the light of our proposal. Certain long standing puzzles, including absence of any magnetic phase transition in La2CoO3 is explained in terms of a novel quantum spin liquid. Some properties of this spin liquid, a liquid of `quantum strings' will be discussed and some predictions made.
A unification of symmetric Z2 spin liquids on kagome lattice

Yuan-Ming Lu

February 14, 2014

PIRSA:14020118

While there is mounting numerical evidence for a gapped Z2 spin liquid in the kagome Heisenberg model, a complete characterization of this topological phase remains to be accomplished. A defining property, the projective symmetry group (PSG) which fixes how the emergent excitations of the spin liquid phase transform under symmetry, remains to be determined. Following a Chern-Simons field theory, we show how PSG determines measurable properties of a Z2 spin liquid, such as the existence of symmetry protected gapless edge states. This fact enables us to unify two distinct types of projected wavefunctions for Z2 spin liquids: the Schwinger-boson states and the fermionic spinon states. We also provide concrete predictions for identifying the spin liquid ground state on the kagome lattice.
How universal is the entanglement spectrum?

Anushya Chandran Perimeter Institute for Theoretical Physics

February 14, 2014

PIRSA:14020132

It is now commonly believed that the ground state entanglement spectrum (ES) exhibits universal features characteristic of a given phase. In this talk, I will present evidence to the contrary. I will show that the entanglement Hamiltonian can undergo quantum phase transitions in which its ground state and low energy spectrum exhibit singular changes, even when the physical system remains in the same phase. For broken symmetry problems, this implies that the ES and the Renyi entropies can mislead entirely, while for quantum Hall systems the ES has much less universal content than assumed to date. I will also discuss the consequences of the eigenstate thermalization hypothesis for the entanglement Hamiltonian, showing that a pure state in a sub-system can capture the properties of the reduced density matrix.
Are non-Fermi-liquids stable to pairing?

Max Metlitski Massachusetts Institute of Technology (MIT) - Department of Physics

February 13, 2014

PIRSA:14020143

States of matter with a sharp Fermi-surface but no well-defined Landau
quasiparticles are expected to arise in a number of physical systems.
Examples include i) quantum critical points associated with the onset
of order in metals, ii) the spinon Fermi-surface (U(1) spin-liquid)
state of a Mott insulator and iii) the Halperin-Lee-Read composite
fermion charge liquid state of a half-filled Landau level. In this
talk, I will use renormalization group techniques to investigate
possible instabilities of such non-Fermi-liquids to pairing. I will
show that for a large class of phase transitions in metals, the
attractive interaction mediated by order parameter fluctuations always
leads to a superconducting instability, which preempts the
non-Fermi-liquid effects. On the other hand, the spinon Fermi-surface
and the Halperin-Lee-Read states are stable against pairing for a
sufficiently weak attractive short-range interaction. However, once
the strength of attraction exceeds a critical value, pairing sets in.
I will describe the ensuing quantum phase transition between i) the
U(1) and the Z_2 spin-liquid states, and ii) the Halperin-Lee-Read and
Moore-Read states.
Gauging symmetry of 2D topological phases

Zhenghan Wang Microsoft Corporation

February 13, 2014

PIRSA:14020125

I will discuss the mathematical framework for gauging a local unitary finite group symmetry of a 2D topological phase of matter.

Title	Speaker(s)	Date	Talk Type	Info link
Early Universe phenomenology after BICEP	Matias Zaldarriaga	2014-04-04	Conference	View details
The Importance of Being Curved	Matthew Kleban	2014-04-04	Conference	View details
B modes for galaxy surveys	Marc Kamionkowski	2014-04-04	Conference	View details
Prospects for Future Measurements	Douglas Scott, Mark Halpern, Barth Netterfield, Rachel Bean, Matt Dobbs	2014-04-04	Conference	View details
Results from BICEP 2	Christopher Sheehy	2014-04-04	Conference	View details
Overview	Kendrick Smith	2014-04-04	Conference	View details
Many-body localization with dipoles	Chris Laumann	2014-02-14	Conference	View details
Low Spin State Mott Insulators and Emergence of novel Quantum Spin Liquids	Baskaran Ganapathy	2014-02-14	Conference	View details
A unification of symmetric Z2 spin liquids on kagome lattice	Yuan-Ming Lu	2014-02-14	Conference	View details
How universal is the entanglement spectrum?	Anushya Chandran	2014-02-14	Conference	View details
Are non-Fermi-liquids stable to pairing?	Max Metlitski	2014-02-13	Conference	View details
Gauging symmetry of 2D topological phases	Zhenghan Wang	2014-02-13	Conference	View details

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Format results

Early Universe phenomenology after BICEP

The Importance of Being Curved

B modes for galaxy surveys

Prospects for Future Measurements

Results from BICEP 2

Overview

Many-body localization with dipoles

Low Spin State Mott Insulators and Emergence of novel Quantum Spin Liquids

A unification of symmetric Z2 spin liquids on kagome lattice

How universal is the entanglement spectrum?

Are non-Fermi-liquids stable to pairing?

Gauging symmetry of 2D topological phases

Early Universe phenomenology after BICEP

The Importance of Being Curved

B modes for galaxy surveys

Prospects for Future Measurements

Results from BICEP 2

Overview

Many-body localization with dipoles

Low Spin State Mott Insulators and Emergence of novel Quantum Spin Liquids

A unification of symmetric Z2 spin liquids on kagome lattice

How universal is the entanglement spectrum?

Are non-Fermi-liquids stable to pairing?

Gauging symmetry of 2D topological phases