Format results
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Quantum tunneling with a Lorentzian path integral
Laura Sberna - University of Nottingham
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Topological field theories and gapped phases of matter
Lakshya Bhardwaj - Harvard University
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Gravity degrees of freedom on a null surface
Florian Hopfmueller - Nord Quantique
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Entanglement structure and UV regularization in cMERA
Adrian Franco Rubio - University of Vienna
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Lorentzian quantum cosmology
Job Feldbrugge - Perimeter Institute for Theoretical Physics
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The holographic dual to general covariance
Vasudev Shyam - Stealth Startup
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Entanglement entropy of scalar fields in causal set theory
Yasaman Kouchekzadeh Yazdi - Dublin Institute For Advanced Studies
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Rethinking time at the Big Bang
Elizabeth Gould - Arthur B. McDonald Canadian Astroparticle Physics Research Institute
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Relative entropy with a twist
Matthew Beach - Amazon.com
Quantum relative entropy is a measure of the indistinguishability of two quantum states in the same Hilbert space. I will discuss the relative entropy between a state with periodic boundary conditions and one with twisted boundary conditions for a free 1+1 CFT with c=1. I will also highlight the… -
Quantum critical responses via holographic models and conformal perturbation theory
We investigate response functions near quantum critical points, allowing for finite temperature and a mild deformation by a relevant scalar. When the quantum critical point is described by a conformal field theory, we use conformal perturbation theory and holography to determine the two leading… -
Quantum tunneling with a Lorentzian path integral
Laura Sberna - University of Nottingham
We describe the tunneling of a quantum mechanical particle with a Lorentzian (realtime) path integral. The analysis is made concrete by application to the inverted harmonic oscillator potential, where the path integral is known exactly. We apply Picard-Lefschetz theory to the time integral of the… -
Rise of non-perturbative effects below the upper critical dimension
Extracting low energy universal data of quantum critical systems is a task whose difficulty increases with decreasing dimension. The increasing strength of quantum fluctuations can be tamed by using renormalization group (RG) schemes based on dimensional regularization close to the upper critical… -
Topological field theories and gapped phases of matter
Lakshya Bhardwaj - Harvard University
I will introduce the idea that topological field theories describe the low-energy properties of gapped local quantum systems. This idea has proved fruitful in recent studies of gapped phases of matter. -
Gravity degrees of freedom on a null surface
Florian Hopfmueller - Nord Quantique
A canonical analysis for general relativity is performed on a null surface without fixing the diffeomorphism gauge, and the canonical pairs of configuration and momentum variables are derived. Next to the well-known spin-2 pair, also spin-1 and spin-0 pairs are identified. The boundary action for a… -
Entanglement structure and UV regularization in cMERA
Adrian Franco Rubio - University of Vienna
We give an introduction to cMERA, a continuous tensor networks ansatz for ground states of QFTs. We also explore a particular feature of it: an intrinsic length scale that acts as an ultraviolet cutoff. We provide evidence for the existence of this cutoff based on the entanglement structure of a… -
Lorentzian quantum cosmology
Job Feldbrugge - Perimeter Institute for Theoretical Physics
Using Picard-Lefschetz theory we show that the Lorentzian path integral forms a good starting point for quantum cosmology which avoids the conformal factor problem present in Euclidean gravity. We study the Lorentzian path integral for a homogeneous and isotropic model with a positive cosmological… -
The holographic dual to general covariance
Vasudev Shyam - Stealth Startup
One of the defining features of holography is the geometerization of the renormalization group scale. This means that when a quantum field theory is holographically dual to a bulk gravity theory, then the direction normal to the boundary in the bulk (the `radial' direction) is to be interpreted as… -
Entanglement entropy of scalar fields in causal set theory
Yasaman Kouchekzadeh Yazdi - Dublin Institute For Advanced Studies
Entanglement entropy is now widely accepted as having deep connections with quantum gravity. It is therefore desirable to understand it in the context of causal sets, especially since they provide in a natural and covariant manner the UV cutoff needed to render entanglement entropy finite. Defining… -
Dualities for chiral algebras from S-duality
Miroslav Rapcak - Qminers
During past few decades, string theory has been used as a source of conjectural dualities in various areas of physics and mathematics. We have extended these applications of string dualities to the study of chiral algebras in 2d CFT. In this talk, I will sketch how to use S-duality of D3-D5-NS5… -
Rethinking time at the Big Bang
Elizabeth Gould - Arthur B. McDonald Canadian Astroparticle Physics Research Institute
I will discuss two ways in which revising the notion of time at the Big Bang will lead to testable predictions. I will then contrast these predictions against standard ΛCDM scenario, and cosmological observations. The first model, Holographic Cosmology, is based on a 3d quantum field theory without…