Talks

10801 - 10812 of 16856 Results

Exact Calculations in the 1D Continuum for DFT and Beyond

November 27, 2012

PIRSA:12110085
Bootstrapping CFTs with the Extremal Functional Method

Miguel Paulos École Normale Supérieure - PSL

November 27, 2012

PIRSA:12110049

Quantum Fields and Strings
Bubble Baryogenesis

Gilly Elor University of California, Berkeley

November 27, 2012

PIRSA:12110091

Cosmology
Mass and Tension (momentum) Sum Rules in AdS (dS)

Jennie Traschen University of Massachusetts Amherst

November 27, 2012

PIRSA:12110042

Quantum Gravity
Statistical Mechanics - Lecture 12

John Berlinsky McMaster University

November 27, 2012

PIRSA:12110034
Quantum Field Theory 2 - Lecture 12

Francois David CEA Saclay

November 27, 2012

PIRSA:12110015

Quantum Fields and Strings
Statistical Mechanics - Lecture 11

John Berlinsky McMaster University

November 26, 2012

PIRSA:12110033
Quantum Field Theory 2 - Lecture 11

Francois David CEA Saclay

November 26, 2012

PIRSA:12110014

Quantum Fields and Strings
Statistical Mechanics - Lecture 10

John Berlinsky McMaster University

November 23, 2012

PIRSA:12110030
Quantum Field Theory 2 - Lecture 10

Francois David CEA Saclay

November 23, 2012

PIRSA:12110011

Quantum Fields and Strings
Dynamical Capture Compact Binary Mergers

William East Perimeter Institute for Theoretical Physics

November 22, 2012

PIRSA:12110054

Strong Gravity
Holography for inflation using conformal perturbation theory.

Paul McFadden Durham University

November 22, 2012

PIRSA:12110078

Cosmology

Exact Calculations in the 1D Continuum for DFT and Beyond

November 27, 2012

PIRSA:12110085

Most applications of the density matrix renormalization group (DMRG) have been to lattice models with short range interactions. But recent developments in DMRG technology open the door to studying continuum systems with long-range interactions in one dimension (1d). One key motivation is simulating cold atom experiments, where it is possible to engineer Hamiltonians of precisely this type. We have been applying DMRG in the 1d continuum with another motivation: to investigate and improve density functional theory (DFT). DFT has exact mathematical foundations, but in practice one must use approximations. These approximations work incredibly well for weakly correlated systems yet fail when correlations are strong. Improving DFT directly for realistic 3d systems is hard because few systems can be solved exactly. By working in the 1d continuum instead, we can use the power of DMRG to study DFT. We can implement both the exact DFT formalism and standard DFT approximations. After showing how to overcome the challenges in performing these calculations, I will discuss some of the key questions we are investigating, for example, the ability of DFT to predict gaps of insulating systems.
Bootstrapping CFTs with the Extremal Functional Method

Miguel Paulos École Normale Supérieure - PSL

November 27, 2012

PIRSA:12110049

Quantum Fields and Strings

The existence of a positive linear functional acting on the space of (differences between) conformal blocks has been shown to rule out regions in the parameter space of conformal field theories (CFTs). We argue that at the boundary of the allowed region the extremal functional contains, in principle, enough information to determine the dimensions and OPE coefficients of an infinite number of operators appearing in the correlator under analysis. Based on this idea we develop the Extremal Functional Method (EFM), a numerical procedure for deriving the spectrum and OPE coefficients of CFTs lying on the boundary (of solution space). We test the EFM by using it to rederive the low lying spectrum and OPE coefficients of the 2d Ising model based solely on the dimension of a single scalar quasi-primary -- no Virasoro algebra required. Our work serves as a benchmark for applications to more interesting, less known CFTs in the near future, such as the 3d Ising model.
Bubble Baryogenesis

Gilly Elor University of California, Berkeley

November 27, 2012

PIRSA:12110091

Cosmology
Mass and Tension (momentum) Sum Rules in AdS (dS)

Jennie Traschen University of Massachusetts Amherst

November 27, 2012

PIRSA:12110042

Quantum Gravity

The stress-energy tensor in a conformal field theory has zero trace. Hence AdS boundary stress-tensors are traceless by construction, to match this property of the dual CFT. An elegant (aka nifty) construction based on the conformal isometry of AdS will be presented which shows that in an asymptotically AdS spacetime, the sum of the ADM mass and the ADM tensions is zero. This result follows strictly from the gravitational point of view- that is, the Einstein equations and the definitions of the ADM charges. Further, it turns out that perturbative stress-energy sources in an asymptotically AdS spacetime must satisfy a local version of this constraint, namely that the sum of the energy density minus the pressures equals zero. The situation with positive cosmological constant is both similar and distinct in interesting ways, which will be briefly discussed. The analogous (analytically continued) conformal isometry in dS is the root of the ``k^4 “ power spectrum for causal cosmological perturbations. Work in progress (speculations) will be presented about a corresponding sum-rule for gravitational charges defined at future infinity in a spacetime that approaches dS at late times.
Statistical Mechanics - Lecture 12

John Berlinsky McMaster University

November 27, 2012

PIRSA:12110034
Quantum Field Theory 2 - Lecture 12

Francois David CEA Saclay

November 27, 2012

PIRSA:12110015

Quantum Fields and Strings
Statistical Mechanics - Lecture 11

John Berlinsky McMaster University

November 26, 2012

PIRSA:12110033
Quantum Field Theory 2 - Lecture 11

Francois David CEA Saclay

November 26, 2012

PIRSA:12110014

Quantum Fields and Strings
Statistical Mechanics - Lecture 10

John Berlinsky McMaster University

November 23, 2012

PIRSA:12110030
Quantum Field Theory 2 - Lecture 10

Francois David CEA Saclay

November 23, 2012

PIRSA:12110011

Quantum Fields and Strings
Dynamical Capture Compact Binary Mergers

William East Perimeter Institute for Theoretical Physics

November 22, 2012

PIRSA:12110054

Strong Gravity
Holography for inflation using conformal perturbation theory.

Paul McFadden Durham University

November 22, 2012

PIRSA:12110078

Cosmology

Holographic cosmology maps cosmological time evolution to the inverse RG ﬂow of a dual three-dimensional QFT. In cases where this RG ﬂow connects two closely separated ﬁxed points, QFT correlators may be calculated perturbatively in terms of the conformal ﬁeld theory associated with one of the ﬁxed points, even when the dual QFT is at strong coupling. Realising slow-roll inﬂation in these terms, we show how to derive standard slow-roll inﬂationary power spectra and non-Gaussianities through purely holographic calculations. The form of slow-roll inﬂationary correlators is seen to be determined by the perturbative breaking of conformal symmetry away from the ﬁxed point.

Title	Date	Collection	Type	Info
Exact Calculations in the 1D Continuum for DFT and Beyond	2012‑11‑27	Quantum Matter	Scientific Series	View details
Bootstrapping CFTs with the Extremal Functional Method	2012‑11‑27	Quantum Fields and Strings	Scientific Series	View details
Bubble Baryogenesis	2012‑11‑27	Particle Physics	Scientific Series	View details
Mass and Tension (momentum) Sum Rules in AdS (dS)	2012‑11‑27	Cosmology and Gravitation	Scientific Series	View details
Statistical Mechanics - Lecture 12	2012‑11‑27	12/13 PSI - Statistical Mechanics	Course	View details
Quantum Field Theory 2 - Lecture 12	2012‑11‑27	12/13 PSI - Quantum Field Theory 2	Course	View details
Statistical Mechanics - Lecture 11	2012‑11‑26	12/13 PSI - Statistical Mechanics	Course	View details
Quantum Field Theory 2 - Lecture 11	2012‑11‑26	12/13 PSI - Quantum Field Theory 2	Course	View details
Statistical Mechanics - Lecture 10	2012‑11‑23	12/13 PSI - Statistical Mechanics	Course	View details
Quantum Field Theory 2 - Lecture 10	2012‑11‑23	12/13 PSI - Quantum Field Theory 2	Course	View details
Dynamical Capture Compact Binary Mergers	2012‑11‑22	Strong Gravity	Scientific Series	View details
Holography for inflation using conformal perturbation theory.	2012‑11‑22	Cosmology and Gravitation	Scientific Series	View details

Format results