Talks

10309 - 10320 of 16754 Results

AMS02 results support the secondary origin of cosmic ray positrons

Kfir Blum

May 03, 2013

PIRSA:13050015

Particle Physics
An Infalling Observer in AdS/CFT and the Information Paradox

Suvrat Raju

May 03, 2013

PIRSA:13050016

Quantum Fields and Strings
Dangerous Curves: How I Learned To Stop Worrying and Love the Calculus

Jennifer Ouellette Freelance Writer

May 01, 2013

PIRSA:13050004
Unconventional Magnetism and Superconductivity in 3 Dimensional Doped Mott Insulators

Baskaran Ganapathy Institute of Mathematical Sciences

April 30, 2013

PIRSA:13040140

Condensed Matter
Quantum measurements constrained by symmetry

Leon Loveridge University of York

April 30, 2013

PIRSA:13040124

Quantum Foundations
Gromov-Witten Invariants from 2D Gauge Theories

Joshua Lapan Harvard University

April 30, 2013

PIRSA:13040141

Quantum Fields and Strings
From topological insulator to weak scale flavor physics

Sichun Sun University of Washington

April 30, 2013

PIRSA:13040126

Particle Physics
Transporting non-Gaussianity from sub- to super- horizon scales

David Mulryne Queen Mary University of London

April 30, 2013

PIRSA:13040128

Cosmology
Laws of thermodynamics beyond the von Neumann regime

Oscar Dahlsten City University of Hong Kong

April 29, 2013

PIRSA:13040112

Quantum Foundations
12/13 PSI - Explorations in String Theory Lecture 15

Pedro Vieira Perimeter Institute for Theoretical Physics

April 26, 2013

PIRSA:13040102

Quantum Fields and Strings
12/13 PSI - Explorations in Cosmology Lecture 15

Matthew Johnson York University

April 26, 2013

PIRSA:13040080

Cosmology
12/13 PSI - Explorations in Condensed Matter Lecture 15

Guifre Vidal Alphabet (United States)

Xiao-Gang Wen Massachusetts Institute of Technology (MIT) - Department of Physics

April 26, 2013

PIRSA:13040061

Condensed Matter

AMS02 results support the secondary origin of cosmic ray positrons

Kfir Blum

May 03, 2013

PIRSA:13050015

Particle 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.
An Infalling Observer in AdS/CFT and the Information Paradox

Suvrat Raju

May 03, 2013

PIRSA:13050016

Quantum Fields and Strings

We reconstruct the experience of an infalling observer using the AdS/CFT correspondence. We write operators both outside and inside the black hole in terms of CFT operators. Our construction provides a natural realization of black hole complementarity, and a way of preserving information without the need for firewalls.
Dangerous Curves: How I Learned To Stop Worrying and Love the Calculus

Jennifer Ouellette Freelance Writer

May 01, 2013

PIRSA:13050004

Based on her book, The Calculus Diaries, join, Jennifer Ouellette as she shows how calculus can be applied to everything from gas mileage, diet, the rides at Disneyland, surfing in Hawaii, shooting craps in Vegas and warding off zombies. Even the mathematically challenged, can-and-should learn the fundamentals of the universal language.
Unconventional Magnetism and Superconductivity in 3 Dimensional Doped Mott Insulators

Baskaran Ganapathy Institute of Mathematical Sciences

April 30, 2013

PIRSA:13040140

Condensed Matter

Utilizing a variety and also constraints offered by quantum and solid state chemistry, we discuss possibilities of unconventional quantum magnetism and superconductivity in doped 3 dimensional Mott insulators. Some of the possibilities are quantum spin liquid states having pseudo fermi surface coexisting with long range magnetic order, 3 dimensional emergent gauge fields and unconventional superconducting order parameter symmetry. We present a few realistic models to illustrate this and use our theory to understand anomalous behavior of certain double perovskite compounds.
Quantum measurements constrained by symmetry

Leon Loveridge University of York

April 30, 2013

PIRSA:13040124

Quantum Foundations

The Wigner-Araki-Yanase (WAY) theorem delineates circumstances under which a class of quantum measurements is ruled out. Specifically, it states that any observable (given as a self adjoint operator) not commuting with an additive conserved quantity of a quantum system and measuring apparatus combined admits no repeatable measurements. I'll review the content of this theorem and present some new work which generalises and strengthens the existing results. The observation that the WAY constraint vanishes if the observable-to-be-measured is ``relativised'' (in a suitable sense) points to interesting links with quantum reference frames and superselection rules. I'll discuss some of these connections and raise some open questions.
Gromov-Witten Invariants from 2D Gauge Theories

Joshua Lapan Harvard University

April 30, 2013

PIRSA:13040141

Quantum Fields and Strings

It has been known for twenty years that a class of two-dimensional gauge theories are intimately connected to toric geometry, as well as to hypersurfaces or complete intersections in a toric varieties, and to generalizations thereof. Under renormalization group flow, the two-dimensional gauge theory flows to a conformal field theory that describes string propagation on the associated geometry. This provides a connection between certain quantities in the gauge theory and topological invariants of the associated geometry. In this talk, I will explain how recent results show that, for Calabi-Yau geometries, the partition function for each gauge theory computes the Kahler potential on the Kahler moduli of the associated geometry. The result is expressed in terms of a Barnes' integral and is readily evaluated in a series expansion around special points in the moduli space (e.g., large volume), providing a fairly efficient way to compute Gromov-Witten invariants of the associated geometry.
From topological insulator to weak scale flavor physics

Sichun Sun University of Washington

April 30, 2013

PIRSA:13040126

Particle Physics

In this talk, I will start with briefly introducing some universal physics behind quantum hall and topological insulator , which inspired a BSM flavor model. It intimately relates deconstructed little Higgs to flavor structure: fermion masses, CKM etc. This new cousin of little Higgs, we call it little flavor, shares a 10-20 Tev cut-off scale with little Higgs, so as to explain flavor structure at surprisingly low scale without rising FCNC problem.
Transporting non-Gaussianity from sub- to super- horizon scales

David Mulryne Queen Mary University of London

April 30, 2013

PIRSA:13040128

Cosmology

The non-Gaussian statistics of the primordial density perturbation have become a key test of the inflationary scenario of the very early universe. Currently many techniques are used to calculate the non-Gaussian signatures of a given model of inflation. In particular, simple super-horizon techniques such as the deltaN formalism are often used for models with more than one field, while more technical field theory techniques, referred to as the In-In formalism, are typically used for models where the quantum sub-horizon evolution is important. Recently we have been developing an alternative point of view, called the transport approach. This framework highlights the connections between these other techniques and unifies them. Moreover, since it reduces the problem of calculating the statistics to that of solving a set of coupled ODEs, numerical implementations of the system are extremely simple.
Laws of thermodynamics beyond the von Neumann regime

Oscar Dahlsten City University of Hong Kong

April 29, 2013

PIRSA:13040112

Quantum Foundations

A recent development in information theory is the generalisation of quantum Shannon information theory to the operationally motivated smooth entropy information theory, which originates in quantum cryptography research. In a series of papers the first steps have been taken towards creating a statistical mechanics based on smooth entropy information theory. This approach turns out to allow us to answer questions one might not have thought were possible in statistical mechanics, such as how much work one can extract in a given realisation, as a function of the failure-probability. This is in contrast to the standard approach which makes statements about average work. Here we formulate the laws of thermodynamics that this new approach gives rise to. We show in particular that the Second Law needs to be tightened. The new laws are motivated by our main quantitative result which states how much work one can extract or must invest in order to affect a given state change with a given probability of success. For systems composed of very large numbers of identical and uncorrelated subsystems, which we call the von Neumann regime, we recover the standard von Neumann entropy statements.

Joint work with Egloff, Renner and Vedral

http://arxiv.org/abs/1207.0434
12/13 PSI - Explorations in String Theory Lecture 15

Pedro Vieira Perimeter Institute for Theoretical Physics

April 26, 2013

PIRSA:13040102

Quantum Fields and Strings
12/13 PSI - Explorations in Cosmology Lecture 15

Matthew Johnson York University

April 26, 2013

PIRSA:13040080

Cosmology
12/13 PSI - Explorations in Condensed Matter Lecture 15

Guifre Vidal Alphabet (United States)

Xiao-Gang Wen Massachusetts Institute of Technology (MIT) - Department of Physics

April 26, 2013

PIRSA:13040061

Condensed Matter

Title	Date	Collection	Type	Info
AMS02 results support the secondary origin of cosmic ray positrons	2013‑05‑03		Scientific Series	View details
An Infalling Observer in AdS/CFT and the Information Paradox	2013‑05‑03	Quantum Fields and Strings	Scientific Series	View details
Dangerous Curves: How I Learned To Stop Worrying and Love the Calculus	2013‑05‑01	Public Lecture Series	Public Lectures	View details
Unconventional Magnetism and Superconductivity in 3 Dimensional Doped Mott Insulators	2013‑04‑30	Quantum Matter	Scientific Series	View details
Quantum measurements constrained by symmetry	2013‑04‑30	Quantum Foundations	Scientific Series	View details
Gromov-Witten Invariants from 2D Gauge Theories	2013‑04‑30	Quantum Fields and Strings	Scientific Series	View details
From topological insulator to weak scale flavor physics	2013‑04‑30	Particle Physics	Scientific Series	View details
Transporting non-Gaussianity from sub- to super- horizon scales	2013‑04‑30	Cosmology and Gravitation	Scientific Series	View details
Laws of thermodynamics beyond the von Neumann regime	2013‑04‑29	Perimeter Institute Quantum Discussions	Scientific Series	View details
12/13 PSI - Explorations in String Theory Lecture 15	2013‑04‑26	12/13 PSI - Eplorations in String Theory	Course	View details
12/13 PSI - Explorations in Cosmology Lecture 15	2013‑04‑26	12/13 PSI - Explorations in Cosmology	Course	View details
12/13 PSI - Explorations in Condensed Matter Lecture 15	2013‑04‑26	12/13 PSI - Explorations in Condensed Matter	Course	View details

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