High Energy Physics

Displaying 1729 - 1740 of 3107

Phenomenology of spontaneous wave-function collapse models

Angelo Bassi University of Trieste
May 27, 2013

PIRSA:13050066
High Energy Physics
Quantum Mechanics and Spacetime

Bill Unruh University of British Columbia
May 27, 2013

PIRSA:13050060
High Energy Physics
Bipartite Graphs, Quivers and Gauge Theories

Yang-Hui He University of London
May 14, 2013

PIRSA:13050020
High Energy Physics
A gauge theory generalization of the fermion-doubling theorem

John McGreevy University of California, San Diego
May 10, 2013

PIRSA:13050050
High Energy Physics

Condensed Matter
Directed Influence in the RG Flow

Glen Evenbly Georgia Institute of Technology
May 09, 2013

PIRSA:13050041
High Energy Physics
Searching for Spin Liquids

Steven White University of California, Irvine
May 09, 2013

PIRSA:13050039
High Energy Physics

Condensed Matter
Quantum renormalization group and AdS/CFT

Sung-Sik Lee McMaster University
May 08, 2013

PIRSA:13050036
High Energy Physics
Impossible symmetry enriched topological phases in 2D and their realization on 3D surface

Xie Chen California Institute of Technology
May 07, 2013

PIRSA:13050033
High Energy Physics
Field theory, Wave function, and Defects of Symmetry Protected Topological Phases

Cenke Xu University of California, Santa Barbara
May 07, 2013

PIRSA:13050031
High Energy Physics
Asymmetry protected emergent E8 symmetry

Brian Swingle Brandeis University
May 06, 2013

PIRSA:13050027
High Energy Physics
Protected edge modes without symmetry

Michael Levin University of Chicago
May 06, 2013

PIRSA:13050026
High Energy Physics
AMS02 results support the secondary origin of cosmic ray positrons

Kfir Blum
May 03, 2013

PIRSA:13050015
High Energy Physics

Phenomenology of spontaneous wave-function collapse models

Angelo Bassi University of Trieste
May 27, 2013

PIRSA:13050066
High Energy Physics
Models of spontaneous wave function collapse make predictions, which are different from those of standard quantum mechanics. Indeed, these models can be considered as a rival theory, against which the standard theory can be tested, in pretty much the same way in which parametrized post-Newtonian gravitational theories are rival theories of general relativity. The predictions of collapse models almost coincide with those of standard quantum mechanics at the microscopic level, as these models have to account for the microscopic world, as we know it. Departures become significant when the size of the system increases. However, for larger systems environmental influences become more and more difficult to eliminate. This is the reason why it is tricky to test collapse models experimentally, and so far no decisive test has been performed. We will review the main phenomenological properties of collapse models, in particular the so-called amplification mechanics, as well as the main models, which are debated in the literature (GRW, CSL, QMUPL, DP). We will review the lower bounds on the collapse parameter, and more importantly the upper bounds set by available experimental data. This data come both from experimental tests on earth, and from cosmological observations.
Quantum Mechanics and Spacetime

Bill Unruh University of British Columbia
May 27, 2013

PIRSA:13050060
High Energy Physics
Bipartite Graphs, Quivers and Gauge Theories

Yang-Hui He University of London
May 14, 2013

PIRSA:13050020
High Energy Physics
We discuss how bipartite graphs on Riemann surfaces encapture a wealth of information about the physics of large classes of supersymmetric gauge theories, especially those with quiver structure and arising from the AdS/CFT context. The correspondence between the gauge theory, the underlying algebraic geometry of it space of vacua, the combinatorics of dimers and toric varieties, as well as the number theory of dessin d'enfants becomes particular intricate under this light.
A gauge theory generalization of the fermion-doubling theorem

John McGreevy University of California, San Diego
May 10, 2013

PIRSA:13050050
High Energy Physics

Condensed Matter
This talk is about obstructions to symmetry-preserving regulators of quantum field theories in 3+1 dimensions. New examples of such obstructions can be found using the fact that 4+1-dimensional SPT states are characterized by their edge states.
(Based on work in progress with S.M. Kravec.)
Directed Influence in the RG Flow

Glen Evenbly Georgia Institute of Technology
May 09, 2013

PIRSA:13050041
High Energy Physics
Given two lattice Hamiltonians H_1 and H_2 that are identical everywhere except on a local region R of the lattice, we propose a relationship between their ground states psi_1 and psi_2. Specifically, assuming the states can be represented as multi-scale entanglement renormalization ansatz (MERA), we propose a principle of directed influence which asserts that the tensors in the MERA’s that represent the ground states can be chosen to be identical everywhere except within a specific, localized region of the tensor network. The validity of this principle is justified by demonstrating it to follow from Wilson's renormalization ideas towards systems with manifestly separated energy scales. This result is shown, through numerical examples, to have practical applications towards the efficient simulation of systems with impurities, boundaries and interfaces, and also argued to provide useful insights towards holographic representations of quantum states.
Searching for Spin Liquids

Steven White University of California, Irvine
May 09, 2013

PIRSA:13050039
High Energy Physics

Condensed Matter
Quantum renormalization group and AdS/CFT

Sung-Sik Lee McMaster University
May 08, 2013

PIRSA:13050036
High Energy Physics
In this talk, I will discuss about the notion of quantum renormalization group, and explain how (D+1)-dimensional gravitational theories naturally emerge as dual descriptions for D-dimensional quantum field theories. It will be argued that the dynamical gravitational field in the bulk encodes the entanglement between low energy modes and high energy modes of the corresponding quantum field theory.
Impossible symmetry enriched topological phases in 2D and their realization on 3D surface

Xie Chen California Institute of Technology
May 07, 2013

PIRSA:13050033
High Energy Physics
In quantum systems with symmetry, the same topological phase can be enriched by symmetry in different ways, resulting in different symmetry transformations of the superselection sectors in the phase. However, not all symmetry transformations are allowed on the superselection sectors in topological phases in purely 2D systems. In this talk, I will discuss some examples of such symmetry enrichment of topological phases, which seem to be consistent with the fusion and braiding rules of the superselection sectors in the theory but are nonetheless impossible to realize in 2D. Interestingly, we show further that they can be realized on the surface of a 3D gapped system with a topologically trivial bulk.
Field theory, Wave function, and Defects of Symmetry Protected Topological Phases

Cenke Xu University of California, Santa Barbara
May 07, 2013

PIRSA:13050031
High Energy Physics
Asymmetry protected emergent E8 symmetry

Brian Swingle Brandeis University
May 06, 2013

PIRSA:13050027
High Energy Physics
The E8 state of bosons is a 2+1d gapped phase of matter which has no topological entanglement entropy but has protected chiral edge states in the absence of any symmetry. This peculiar state is interesting in part because it sits at the boundary between short- and long-range entangled phases of matter. When the system is translation invariant and for special choices of parameters, the edge states form the chiral half of a 1+1d conformal field theory - an E8 level 1 Wess-Zumino-Witten model. However, in general the velocities of different edge channels are different and the system does not have conformal symmetry. We show that by considering the most general microscopic Hamiltonian, in particular by relaxing the constraint of translation invariance and adding disorder, conformal symmetry remerges in the low energy limit. The disordered fixed point has all velocities equal and is the E8 level 1 WZW model. Hence a highly entangled and highly symmetric system emerges, but only when the microscopic Hamiltonian is completely asymmetric.
Protected edge modes without symmetry

Michael Levin University of Chicago
May 06, 2013

PIRSA:13050026
High Energy Physics
Some 2D quantum many-body systems with a bulk energy gap support gapless edge modes which are extremely robust. These modes cannot be gapped out or localized by general classes of interactions or disorder at the edge: they are "protected" by the structure of the bulk phase. Examples of this phenomena include quantum Hall states and 2D topological insulators, among others. Recently, much progress has been made in understanding protected edge modes in non-interacting fermion systems. However, less is known about the interacting case. A basic problem is to predict, for general interacting systems, when such edge modes are present or absent, and to identify the different physical mechanisms that underlie their stability. In this talk, I will discuss this problem in the simplest case: interacting fermion systems without any symmetry.
AMS02 results support the secondary origin of cosmic ray positrons

Kfir Blum
May 03, 2013

PIRSA:13050015
High Energy Physics
We show that the recent AMS02 positron fraction measurement is perfectly consistent with a secondary origin for positrons, and does not require additional primary sources such as pulsars or dark matter. Within the secondary model the AMS02 data imply a cosmic ray propagation time in the
Galaxy of about one Myr and an average traversed interstellar matter density of about 1/cc at a rigidity of 300 GV. These results may hint that high energy cosmic rays are confined to a thin halo of scale height similar to the gaseous disk.

Title	Speaker(s)	Date	Talk Type	Info link
Phenomenology of spontaneous wave-function collapse models	Angelo Bassi	2013-05-27	Conference	View details
Quantum Mechanics and Spacetime	Bill Unruh	2013-05-27	Conference	View details
Bipartite Graphs, Quivers and Gauge Theories	Yang-Hui He	2013-05-14	Scientific Series	View details
A gauge theory generalization of the fermion-doubling theorem	John McGreevy	2013-05-10	Conference	View details
Directed Influence in the RG Flow	Glen Evenbly	2013-05-09	Conference	View details
Searching for Spin Liquids	Steven White	2013-05-09	Conference	View details
Quantum renormalization group and AdS/CFT	Sung-Sik Lee	2013-05-08	Conference	View details
Impossible symmetry enriched topological phases in 2D and their realization on 3D surface	Xie Chen	2013-05-07	Conference	View details
Field theory, Wave function, and Defects of Symmetry Protected Topological Phases	Cenke Xu	2013-05-07	Conference	View details
Asymmetry protected emergent E8 symmetry	Brian Swingle	2013-05-06	Conference	View details
Protected edge modes without symmetry	Michael Levin	2013-05-06	Conference	View details
AMS02 results support the secondary origin of cosmic ray positrons	Kfir Blum	2013-05-03	Scientific Series	View details

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High Energy Physics

Format results

Phenomenology of spontaneous wave-function collapse models

Quantum Mechanics and Spacetime

Bipartite Graphs, Quivers and Gauge Theories

A gauge theory generalization of the fermion-doubling theorem

Directed Influence in the RG Flow

Searching for Spin Liquids

Quantum renormalization group and AdS/CFT

Impossible symmetry enriched topological phases in 2D and their realization on 3D surface

Field theory, Wave function, and Defects of Symmetry Protected Topological Phases

Asymmetry protected emergent E8 symmetry

Protected edge modes without symmetry

AMS02 results support the secondary origin of cosmic ray positrons

Phenomenology of spontaneous wave-function collapse models

Quantum Mechanics and Spacetime

Bipartite Graphs, Quivers and Gauge Theories

A gauge theory generalization of the fermion-doubling theorem

Directed Influence in the RG Flow

Searching for Spin Liquids

Quantum renormalization group and AdS/CFT

Impossible symmetry enriched topological phases in 2D and their realization on 3D surface

Field theory, Wave function, and Defects of Symmetry Protected Topological Phases

Asymmetry protected emergent E8 symmetry

Protected edge modes without symmetry

AMS02 results support the secondary origin of cosmic ray positrons