Scientific Series

Displaying 2929 - 2940 of 4927

The Minimal Modal Interpretation of Quantum Theory
- David Kagan University of Massachusetts Dartmouth
- Jacob Barandes Harvard University
October 14, 2014

PIRSA:14100001
Quantum Physics
Bulk Entanglement Spectrum: From Topological States to Quantum Criticality

Timothy Hsieh Perimeter Institute for Theoretical Physics
October 14, 2014

PIRSA:14100075
Condensed Matter
QQ-CHARACTERS, GAUGE THEORY and non-perturbative Dyson-Schwinger equations

Nikita Nekrasov Stony Brook University

October 14, 2014

PIRSA:14100066
(Non)perturbative QCD and Jet Substructure

Jesse Thaler Massachusetts Institute of Technology (MIT)

October 14, 2014

PIRSA:14100046
Gravitational lensing of the CMB

Gilbert Holder University of Illinois Urbana-Champaign
October 14, 2014

PIRSA:14100084
Astrophysics
Bogomolov and beyond for Calabi-Yau 3-folds

Peng Gao ExodusPoint Capital
October 08, 2014

PIRSA:14100083
High Energy Physics
Non local weak measurements

Aharon Brodutch Institute for Quantum Computing (IQC)
October 07, 2014

PIRSA:14100073
Quantum Physics
On reducing 3d supersymmetric theories to two dimensions

Brian Willett Institute for Advanced Study (IAS)
October 07, 2014

PIRSA:14100005
High Energy Physics
De Sitter Wavefunctionals and the Resummation of Time

Matthew Baumgart Carnegie Mellon University
October 07, 2014

PIRSA:14100051
High Energy Physics
Flux Compactifications Grow Lumps

Claire Zukowski University of California, Berkeley
October 07, 2014

PIRSA:14100081
Astrophysics
Computer Algebra for Theoretical Physics

Edgardo Cheb-Terrab Maplesoft

October 07, 2014

PIRSA:14100068
Probing (beyond) general relativity with compact binaries and gravitational waves

Leo Stein Cornell University
October 02, 2014

PIRSA:14100003
General Relativity & Quantum Cosmology

The Minimal Modal Interpretation of Quantum Theory
- David Kagan University of Massachusetts Dartmouth
- Jacob Barandes Harvard University
October 14, 2014

PIRSA:14100001
Quantum Physics
A persistent mystery of quantum theory is whether it admits an interpretation that is realist, self-consistent, model-independent, and unextravagant in the sense of featuring neither multiple worlds nor pilot waves. In this talk, I will present a new interpretation of quantum theory -- called the minimal modal interpretation (MMI) -- that aims to meet these conditions while also hewing closely to the basic structure of the theory in its widely accepted form. The MMI asserts that quantum systems -- whether closed or open -- have actual states that evolve along kinematical trajectories through their state spaces, and that those trajectories are governed by specific (if approximate) dynamical rules determined by a general new class of conditional probabilities, and in a manner that differs significantly from the de Broglie-Bohm formulation. The MMI is axiomatically parsimonious, leaves the usual dynamical content of quantum theory essentially intact, and includes only metaphysical entities that are either already a standard part of quantum theory or that have counterparts in classical physics. I will also address a number of important issues and implicit assumptions in the foundations community that I believe merit reconsideration and re-evaluation going forward.
Bulk Entanglement Spectrum: From Topological States to Quantum Criticality

Timothy Hsieh Perimeter Institute for Theoretical Physics
October 14, 2014

PIRSA:14100075
Condensed Matter
A quantum phase transition is usually achieved by tuning physical parameters in a Hamiltonian at zero temperature. Here, we demonstrate that the ground state of a topological phase itself encodes critical properties of its transition to a trivial phase. To extract this information, we introduce a partition of the system into two subsystems both of which extend throughout the bulk in all directions. The resulting bulk entanglement spectrum (BES) has a low-lying part that resembles the excitation spectrum of a bulk Hamiltonian, which allows us to probe a topological phase transition from a single wavefunction by tuning either the geometry of the partition or the entanglement temperature. As an example, this remarkable correspondence between topological phase transition and entanglement criticality is rigorously established for integer quantum Hall states. We also implement BES using tensor networks, derive the universality classes of topological phase transitions from the spin-1 chain Haldane phase, and demonstrate that the AKLT wavefunction (and its generalizations) remarkably contains critical six-vertex (and in general eight-vertex) models within it.
QQ-CHARACTERS, GAUGE THEORY and non-perturbative Dyson-Schwinger equations

Nikita Nekrasov Stony Brook University

October 14, 2014

PIRSA:14100066

We report on recent advances in understanding the non-local symmetries of quantum field theory, notably gauge theory. The symmetries relate topologically distinct sectors of the field space. We study these symmetries in some detail in the context of the BPS/CFT correspondence. We also introduce a notion of qq-characters, which generalize the q-characters of quantum affine algebras, introduced by E. Frenkel and N. Reshetikhin, and conjecturally are related to the (q, t)-characters introduced by H. Nakajima. We show that the qq-characters can be used to derive an infinite set of Dyson-Schwinger type relations which imply that the supersymmetric partition functions of four dimensional gauge theory (with surface operators) obey BPZ and KZB-type equations.
(Non)perturbative QCD and Jet Substructure

Jesse Thaler Massachusetts Institute of Technology (MIT)

October 14, 2014

PIRSA:14100046

With the remarkable performance of the ATLAS and CMS detectors, jets at the LHC can now be characterized not just by their overall direction and energy but also by their substructure. At the same time, there has been substantial progress in predicting the properties of jets from first principles. In this talk, I highlight the ways that theoretical studies of jet substructure have enhanced our understanding of QCD, including examples that blur the boundary between perturbative and nonperturbative physics.
Gravitational lensing of the CMB

Gilbert Holder University of Illinois Urbana-Champaign
October 14, 2014

PIRSA:14100084
Astrophysics
Gravitational lensing of the cosmic microwave background is emerging as a useful cosmological tool. Recent measurements have been made by several experiments (including the South Pole Telescope, which will be featured), with rapidly improving precision. These measurements can be used for many purposes, including studying the connection between dark matter and galaxies on large scales, measuring the clustering of matter at z~3, and improving the precision of possible measurements of gravitational radiation from inflation.
Bogomolov and beyond for Calabi-Yau 3-folds

Peng Gao ExodusPoint Capital
October 08, 2014

PIRSA:14100083
High Energy Physics
Non local weak measurements

Aharon Brodutch Institute for Quantum Computing (IQC)
October 07, 2014

PIRSA:14100073
Quantum Physics
Weak measurement is increasingly acknowledged as an important theoretical and experimental tool. Weak values- the results of weak measurements- are often used to understand seemingly paradoxical quantum behavior. Until now however, it was not known how to perform a weak non-local measurement of a general operator. Such a procedure is necessary if we are to take the associated `weak values' seriously as a physical quantity. We propose a novel scheme for performing non-local weak measurement which is based on the principle of quantum erasure. This method can be used for a large class of observables including those related to Hardy's paradox.
On reducing 3d supersymmetric theories to two dimensions

Brian Willett Institute for Advanced Study (IAS)
October 07, 2014

PIRSA:14100005
High Energy Physics
We study the dimensional reduction of 3d QFTs with N=2 supersymmetry. In particular, we are interested in deriving dualities between 2d N=(2,2) theories starting from 3d dualities. Our main tool is the supersymmetric index, ie, the partition function on S^2 x S^1, which formally reduces to the partition function on S^2 as the radius of the circle goes to zero. There are various technical subtleties in this limit of the index which reflect physical subtleties in the reduction of the theories. We reproduce several known 2d N=(2,2) dualities and find evidence for some new ones.
De Sitter Wavefunctionals and the Resummation of Time

Matthew Baumgart Carnegie Mellon University
October 07, 2014

PIRSA:14100051
High Energy Physics
The holographic RG of Anti-De Sitter gives a powerful clue about the underlying AdS/CFT correspondence. The question is whether similar hints can be found for the heretofore elusive holographic dual of De Sitter. The framework of stochastic inflation uses nonperturbative insight to tame bad behavior in the perturbation series of a massless scalar in DS at late times. Remarkably, this fully quantum system loses phase information in the leading approximation, but retains a probabilistic character and allows for a controlled prediction of late time Green's functions. Recasting this as a "resummation of time", we wish understand whether the distributions that result can be thought of as an attractive UV fixed point of a theory
living on a spacelike slice of DS. We derive stochastic inflation via the wavefunctional approach to Quantum Field Theory. This allows for the straightforward implementation of corrections to the original framework.
Flux Compactifications Grow Lumps

Claire Zukowski University of California, Berkeley
October 07, 2014

PIRSA:14100081
Astrophysics
The simplest flux compactifications are highly symmetric—a q-form flux is wrapped uniformly around an extra-dimensional q-sphere. I will discuss a family of solutions that break the internal SO(q+1) symmetry of these solutions down to SO(q)×Z_2, and show that often at least one of them has lower vacuum energy, larger entropy, and is more stable than the symmetric solution. I will describe the phase diagram of lumpy solutions and provide an interpretation in terms of an effective potential. Finally, I will provide evidence that the perturbatively stable vacua have a non-perturbative instability to spontaneously sprout lumps; generically this new decay is exponentially faster than all other known decays of the model.
Computer Algebra for Theoretical Physics

Edgardo Cheb-Terrab Maplesoft

October 07, 2014

PIRSA:14100068

Generally speaking, physicists still experience that computing with paper and pencil is in most cases simpler than computing on a Computer Algebra worksheet. On the other hand, recent developments in the Maple system implemented most of the mathematical objects and mathematics used in theoretical physics computations, and dramatically approximated the notation used in the computer to the one used in paper and pencil, diminishing the learning gap and computer-syntax distraction to a strict minimum. In connection, in this talk the Physics project at Maplesoft is presented and the resulting Physics package illustrated tackling problems in classical and quantum mechanics, general relativity and field theory. In addition to the 10 a.m lecture, there will be a hands-on workshop at 1pm in the Alice Room. Feel free to join!
Probing (beyond) general relativity with compact binaries and gravitational waves

Leo Stein Cornell University
October 02, 2014

PIRSA:14100003
General Relativity & Quantum Cosmology
General relativity enjoys phenomenal success in agreeing with experiments and observations, but it must break down at some point. Astrophysics can give guidance for what type of theory may correct general relativity, if we know which phenomenology to look for. I will discuss the possible corrections to the structure of compact objects, the binary problem, and observations with pulsar timing and gravitational wave detection. These corrections are computed in specific effective theories, such as Einstein-dilaton-Gauss-Bonnet (EdGB) and dynamical Chern-Simons (dCS) gravity, and we may further generalize the common aspects of these theories to build a parametrized framework which captures a large number of effective field theories.

Title	Speaker(s)	Date	Talk Type	Info link
The Minimal Modal Interpretation of Quantum Theory	David Kagan, Jacob Barandes	2014-10-14	Scientific Series	View details
Bulk Entanglement Spectrum: From Topological States to Quantum Criticality	Timothy Hsieh	2014-10-14	Scientific Series	View details
QQ-CHARACTERS, GAUGE THEORY and non-perturbative Dyson-Schwinger equations	Nikita Nekrasov	2014-10-14	Scientific Series	View details
(Non)perturbative QCD and Jet Substructure	Jesse Thaler	2014-10-14	Scientific Series	View details
Gravitational lensing of the CMB	Gilbert Holder	2014-10-14	Scientific Series	View details
Bogomolov and beyond for Calabi-Yau 3-folds	Peng Gao	2014-10-08	Scientific Series	View details
Non local weak measurements	Aharon Brodutch	2014-10-07	Scientific Series	View details
On reducing 3d supersymmetric theories to two dimensions	Brian Willett	2014-10-07	Scientific Series	View details
De Sitter Wavefunctionals and the Resummation of Time	Matthew Baumgart	2014-10-07	Scientific Series	View details
Flux Compactifications Grow Lumps	Claire Zukowski	2014-10-07	Scientific Series	View details
Computer Algebra for Theoretical Physics	Edgardo Cheb-Terrab	2014-10-07	Scientific Series	View details
Probing (beyond) general relativity with compact binaries and gravitational waves	Leo Stein	2014-10-02	Scientific Series	View details

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Format results

The Minimal Modal Interpretation of Quantum Theory

Bulk Entanglement Spectrum: From Topological States to Quantum Criticality

QQ-CHARACTERS, GAUGE THEORY and non-perturbative Dyson-Schwinger equations

(Non)perturbative QCD and Jet Substructure

Gravitational lensing of the CMB

Bogomolov and beyond for Calabi-Yau 3-folds

Non local weak measurements

On reducing 3d supersymmetric theories to two dimensions

De Sitter Wavefunctionals and the Resummation of Time

Flux Compactifications Grow Lumps

Computer Algebra for Theoretical Physics

Probing (beyond) general relativity with compact binaries and gravitational waves

The Minimal Modal Interpretation of Quantum Theory

Bulk Entanglement Spectrum: From Topological States to Quantum Criticality

QQ-CHARACTERS, GAUGE THEORY and non-perturbative Dyson-Schwinger equations

(Non)perturbative QCD and Jet Substructure

Gravitational lensing of the CMB

Bogomolov and beyond for Calabi-Yau 3-folds

Non local weak measurements

On reducing 3d supersymmetric theories to two dimensions

De Sitter Wavefunctionals and the Resummation of Time

Flux Compactifications Grow Lumps

Computer Algebra for Theoretical Physics

Probing (beyond) general relativity with compact binaries and gravitational waves