Scientific Series

Displaying 3025 - 3036 of 5012

Supersymmetric AdS5 solutions in M-theory and Class S SCFT's

Ibrahima Bah
University of Southern California (USC)
July 22, 2014

PIRSA:14070032
Quantum Fields and Strings
Inferring causal structure: a quantum advantage

Katja Ried
Universität Innsbruck
July 17, 2014

PIRSA:14070021
Quantum Foundations
Exploring N=1 theories of class S through Higgsing, dualizing and twisting

Jaewon Song
University of California, San Diego
July 15, 2014

PIRSA:14070024
Quantum Fields and Strings
Improving Mass Measurements Using Many-Body Phase Space

Can Kilic
The University of Texas at Austin
July 15, 2014

PIRSA:14070023
Particle Physics
Cosmological Coincidence Problem
July 15, 2014

PIRSA:14070030
Cosmology
Strong majorization entropic uncentainty relations

Karol Zyczkowski
Jagiellonian University
July 14, 2014

PIRSA:14070017
Quantum Information
TBA
July 08, 2014

PIRSA:14070018
Condensed Matter
Numerical investigations of singularities in general relativity

David Garfinkle
Oakland University
June 26, 2014

PIRSA:14060052
Cosmology
On Quantum Tunnelling

Neil Turok
University of Edinburgh
June 25, 2014

PIRSA:14060051
Cosmology
Gravity, an unexpected journey: from thermodynamics to emergent gravity, Lorentz breaking and back...

Stefano Liberati
SISSA International School for Advanced Studies
June 19, 2014

PIRSA:14060002
Quantum Gravity
Analogue Models of Gravity: The ubiquitous space-time

Stefano Liberati
SISSA International School for Advanced Studies
June 18, 2014

PIRSA:14060000
Quantum Gravity
The Exact Renormalization Group and Higher Spin Holography.

Rob Leigh
University of Illinois Urbana-Champaign
June 17, 2014

PIRSA:14060047
Quantum Fields and Strings

Supersymmetric AdS5 solutions in M-theory and Class S SCFT's

Ibrahima Bah
University of Southern California (USC)
July 22, 2014

PIRSA:14070032
Quantum Fields and Strings
We provide a framework for describing gravity duals of four-dimensional N=1 superconformal field theories obtained by compactifying a stack of M5-branes on a Riemann surface. The gravity solutions are completely specified by two scalar potentials whose pole structures on the Riemann surface correspond to the spectrum of punctures that labels different theories. We discuss how to identify these puncture in gravity.
Inferring causal structure: a quantum advantage

Katja Ried
Universität Innsbruck
July 17, 2014

PIRSA:14070021
Quantum Foundations
A fundamental question in trying to understand the world -- be it classical or quantum -- is why things happen. We seek a causal account of events, and merely noting correlations between them does not provide a satisfactory answer. Classical statistics provides a better alternative: the framework of causal models proved itself a powerful tool for studying causal relations in a range of disciplines. We aim to adapt this formalism to allow for quantum variables and in the process discover a new perspective on how causality is different in the quantum world. Causal inference is a central task in the context of causal models: given observed statistics over a set of variables, one aims to infer how they are causally related. Yet in the seemingly simple case of just two classical variables, this is impossible (unless one makes additional assumptions). I will show how the analogous task for quantum variables can be solved. This quantum advantage is reminiscent of the advantages that quantum mechanics offers in computing and communication, and may lead to similarly rich insights. Our scheme is corroborated by data obtained in collaboration with Kevin Resch's experimental group. Time permitting, I will also address other applications of the quantum causal models. arXiv:1406.5036
Exploring N=1 theories of class S through Higgsing, dualizing and twisting

Jaewon Song
University of California, San Diego
July 15, 2014

PIRSA:14070024
Quantum Fields and Strings
We study a class of 4d N=1 SCFTs obtained from partial compactifications of 6d N=(2, 0) theory on a Riemann surface with punctures. We identify theories corresponding to curves with general type of punctures through nilpotent Higgsing and Seiberg dualities. The `quiver tails' of N=1 class S theories turn out to differ significantly from N=2 counterpart and have interesting properties. Various dual descriptions for such a theory can be found by using colored pair-of-pants decompositions. Especially, we find N=1 analog of Argyres-Seiberg duality for the SQCD with various gauge groups. We compute anomaly coefficients and superconformal indices to verify our proposal.
Improving Mass Measurements Using Many-Body Phase Space

Can Kilic
The University of Texas at Austin
July 15, 2014

PIRSA:14070023
Particle Physics
After the 7 and 8 TeV LHC runs, we have no conclusive evidence of physics beyond the Standard Model, leading us to suspect that even if new physics is discovered during run II, the number of signal events may be limited, making it crucial to optimize measurements for the case of low statistics. I will argue that phase space correlations between subsequent on-shell decays in a cascade contain additional information compared to commonly used kinematic variables, and this can be used to significantly improve the precision and accuracy of mass measurements. The improvement is connected to the properties of the volume element of many-body phase space, and is particularly relevant to the case of low signal statistics.
Cosmological Coincidence Problem
July 15, 2014

PIRSA:14070030
Cosmology
I will try to explain how cosmological coincidence of the two values, the matter energy density and the dark energy density, at the present epoch based on a single scalar field model whith a quartic potential, non-mimimally interacting with gravity. Dark energy in this model originates from the potential energy of the scalar field, which is sourced by the appearance of non-relativistic matter at the time z~ 10^10. No fine tuning of parameter are neccessary.
Strong majorization entropic uncentainty relations

Karol Zyczkowski
Jagiellonian University
July 14, 2014

PIRSA:14070017
Quantum Information
We analyze entropic uncertainty relations in a finite dimensional Hilbert space and derive several strong bounds for the sum of two entropies obtained in projective measurements with respect to any two orthogonal bases. We improve the recent bounds by Coles and Piani, which are known to be stronger than the well known result of Maassen and Uffink. Furthermore, we find a novel bound based on majorization techniques, which also happens to be stronger than the recent results involving largest singular values of submatrices of the unitary matrix connecting both bases. The first set of new bounds give better results for unitary matrices close to the Fourier matrix, while the second one provides a significant improvement in the opposite sectors. Some results derived admit generalization to arbitrary mixed states, so that corresponding bounds are increased by the von Neumann entropy of the measured state. The majorization approach is finally extended to the case of several measurements.
TBA
July 08, 2014

PIRSA:14070018
Condensed Matter
Numerical investigations of singularities in general relativity

David Garfinkle
Oakland University
June 26, 2014

PIRSA:14060052
Cosmology
The singularity theorems of general relativity tell us that spacetime singularities form in gravitational collapse, but tell us very little about the precise nature of these singularities. More information can be found using analytic approximations and numerical simulations. It is conjectured that inside black holes are two types of singularities: one that is spacelike, local, and oscillatory, and the other that is null and weak. This talk will review what numerical simulations of singularities have been done and the extent to which the above conjecture has been verified by the simulations.
On Quantum Tunnelling

Neil Turok
University of Edinburgh
June 25, 2014

PIRSA:14060051
Cosmology
One of the most basic but intriguing properties of quantum systems is their ability to `tunnel' between configurations which are classically disconnected. That is, processes which are classically impossible, are quantum allowed. In this talk I will outline a new, first-principles approach combining the semiclassical approximation with the concepts of post-selection and weak measurement. Its main virtue is to provide a real-time description within which sharp answers can be given to questions such as 'how long did the tunneling take' and 'where was the particle while it was tunneling?' Potential applications span a vast range, from laboratory tests to understanding black hole evaporation, the stability of the electroweak Higgs vacuum and the future of our universe, and the validity (or otherwise) of the "inflationary multiverse" scenario.
Gravity, an unexpected journey: from thermodynamics to emergent gravity, Lorentz breaking and back...

Stefano Liberati
SISSA International School for Advanced Studies
June 19, 2014

PIRSA:14060002
Quantum Gravity
Thermodynamical aspects of gravity have been a tantalising puzzle for more than forty years now and are still at the center of much activity in semiclassical and quantum gravity. We shall explore the possibility that they might hint toward an emergent nature of gravity exploring the possible implications of such hypothesis. Among these we shall focus on the possibility that Lorentz invariance might be only a low energy/emergent feature by discussing viable theoretical frameworks, present constraints and open issues which make this path problematic. In the end we shall focus on black hole thermodynamics in Lorentz breaking gravity by presenting some recent results that seems to hint towards a surprising resilience of thermodynamics aspect of gravity even in these scenarios.
Analogue Models of Gravity: The ubiquitous space-time

Stefano Liberati
SISSA International School for Advanced Studies
June 18, 2014

PIRSA:14060000
Quantum Gravity
Analogies have played a very important role in physics and mathematics, as they provide new ways of looking at problems that permit cross-fertilization of ideas among different branches of science. An analogue gravity model is a generic dynamical system (typically but not always based on condensed matter physics) where the propagation of excitations/perturbations can be described via hyperbolic equations of motion possibly characterized be one single metric element for all the perturbations. We shall review the historical development of this field, some of the systems proposed, and discuss several applications of this fruitful analogy mainly in the context of black hole physics and cosmology. While typical applications are in the realm of classical and quantum field theory on curved spacetime, I shall in the end also discuss recent developments which may provide insights about the possible nature of gravitational dynamics in emergent gravity scenarios.
The Exact Renormalization Group and Higher Spin Holography.

Rob Leigh
University of Illinois Urbana-Champaign
June 17, 2014

PIRSA:14060047
Quantum Fields and Strings

Title	Speaker(s)	Date	Talk Type	Info link
Supersymmetric AdS5 solutions in M-theory and Class S SCFT's	Ibrahima Bah	2014-07-22	Scientific Series	View details
Inferring causal structure: a quantum advantage	Katja Ried	2014-07-17	Scientific Series	View details
Exploring N=1 theories of class S through Higgsing, dualizing and twisting	Jaewon Song	2014-07-15	Scientific Series	View details
Improving Mass Measurements Using Many-Body Phase Space	Can Kilic	2014-07-15	Scientific Series	View details
Cosmological Coincidence Problem		2014-07-15	Scientific Series	View details
Strong majorization entropic uncentainty relations	Karol Zyczkowski	2014-07-14	Scientific Series	View details
TBA		2014-07-08	Scientific Series	View details
Numerical investigations of singularities in general relativity	David Garfinkle	2014-06-26	Scientific Series	View details
On Quantum Tunnelling	Neil Turok	2014-06-25	Scientific Series	View details
Gravity, an unexpected journey: from thermodynamics to emergent gravity, Lorentz breaking and back...	Stefano Liberati	2014-06-19	Scientific Series	View details
Analogue Models of Gravity: The ubiquitous space-time	Stefano Liberati	2014-06-18	Scientific Series	View details
The Exact Renormalization Group and Higher Spin Holography.	Rob Leigh	2014-06-17	Scientific Series	View details

Scientific Series

Format results