Talks

15205 - 15216 of 22545 Results

A CDT Hamiltonian from Horava-Lifshitz gravity

Yuki Sato Nagoya University

March 14, 2013

PIRSA:13030091

General Relativity & Quantum Cosmology
The dynamics of asymptotically anti-de Sitter spacetimes

Claude Warnick

March 14, 2013

PIRSA:13030077

General Relativity & Quantum Cosmology
The Higgs confronts 3 universes at the LHC

Markus Luty University of California, Davis

March 13, 2013

PIRSA:13030095

High Energy Physics
Advanced General Relativity - Lecture 15

Rafael Sorkin Perimeter Institute for Theoretical Physics

March 12, 2013

PIRSA:13030013
Neorealism and the Internal Language of Topoi

Sander Wolters Radboud Universiteit Nijmegen

March 12, 2013

PIRSA:13030107

Quantum Physics
Large N Chern-Simons-matter theories and three dimensional bosonization

Ofer Aharony Weizmann Institute of Science

March 12, 2013

PIRSA:13030106

High Energy Physics
Renormalization of Entanglement Entropy

Markus Luty University of California, Davis

March 12, 2013

PIRSA:13030108

High Energy Physics
Effective field theory approach to quasi-single field inflation

Masahide Yamaguchi Tokyo Institute of Technology

March 12, 2013

PIRSA:13030096

Astrophysics
Efficient Distributed Quantum Computing

Oliver Gray University of Bristol

March 11, 2013

PIRSA:13030104

Quantum Physics
This is What a Scientist Looks Like

Sampa Bhadra York University

Natalia Toro Stanford University

Shohini Ghose Wilfrid Laurier University

March 08, 2013

PIRSA:13030086
One-photon and two-photon switching in graphene and optical nanomaterials

Mahi Singh Western University

March 08, 2013

PIRSA:13030094

Condensed Matter
The Effects of Limited Resources and Opportunities on Women’s Careers in Physics: Results from the Global Survey of Physicists

Rachel Ivie American Institute of Physics

March 08, 2013

PIRSA:13030082

A CDT Hamiltonian from Horava-Lifshitz gravity

Yuki Sato Nagoya University

March 14, 2013

PIRSA:13030091

General Relativity & Quantum Cosmology

Causal Dynamical Triangulations” (CDT) is a lattice theory where aspects of quantum gravity can be studied. Two-dimensional CDT can be solved analytically and the continuum (quantum) Hamiltonian obtained.
In this talk I will show that this continuum Hamiltonian is the one obtained by quantizing two-dimensional projectable Horava-Lifshitz gravity.
The dynamics of asymptotically anti-de Sitter spacetimes

Claude Warnick

March 14, 2013

PIRSA:13030077

General Relativity & Quantum Cosmology

The majority of work on asymptotically anti-de Sitter spacetimes, much of it motivated by the AdS/CFT correspondence, assumes configurations which are either at or close to equilibrium. Recently it has been discovered that genuinely dynamical spacetimes with AdS asymptotics can exhibit some surprising behaviour. In particular, numerical studies suggest AdS is dynamically unstable. I will discuss recent analytical (in)stability results for asymptotically AdS spacetimes, in particular how stability can be affected by boundary conditions at the timelike conformal infinity.
The Higgs confronts 3 universes at the LHC

Markus Luty University of California, Davis

March 13, 2013

PIRSA:13030095

High Energy Physics

The recent discovery of the Higgs boson is a fundamental advance in particle physics. This talk gives a theorist's perspective of the significance of this discovery. The Higgs boson was proposed in the 1960s, but it is best understood in the context of the quest to understand the weak interactions, which began with Fermi's theory of weak interactions almost 80 years ago. This has led to three very different paradigms for the structure of fundamental interactions at the TeV scale: supersymmetry, compositeness/extra dimensions, and anthropic selection. The Large Hadron Collider is the experimentum crucis for deciding between these different possible universes, and the discovery of the Higgs is a crucial clue. This talk will describe these paradigms, the implications of the Higgs discovery for them, and the outlook for further discoveries that would decide between them.
Advanced General Relativity - Lecture 15

Rafael Sorkin Perimeter Institute for Theoretical Physics

March 12, 2013

PIRSA:13030013
Neorealism and the Internal Language of Topoi

Sander Wolters Radboud Universiteit Nijmegen

March 12, 2013

PIRSA:13030107

Quantum Physics

Crudely formulated, the idea of neorealism, in the way that Chris Isham and Andreas Doering use it, means that each theory of physics, in its mathematical formulation should share certain structural properties of classical physics. These properties are chosen to allow some degree of realism in the interpretation (for example, physical variables always have values). Apart from restricting the form of physical theories, neorealism does increase freedom in the shape of physical theories in another way. Theories of physics may be interpreted in other topoi than the category of sets and functions. In my talk I will concentrate on two topos models for quantum theory. The contravariant model of Butterfield, Isham and Doering on the one hand, and the covariant model of Heunen, Landsman and Spitters on the other. I will argue that when we think of the topoi as generalized categories of sets (i.e. when we use the internal perspective of the topoi at hand), these two models are closely related, and both resemble classical physics. I will assume no background knowledge in topos theory.
Large N Chern-Simons-matter theories and three dimensional bosonization

Ofer Aharony Weizmann Institute of Science

March 12, 2013

PIRSA:13030106

High Energy Physics

I will discuss the conformal theories of N complex scalars or fermions in 2+1 dimensions, coupled to a U(N) Chern-Simons (CS) theory at level k. In the large N limit these theories have a high-spin symmetry, and, as I will review, they are dual to Vasiliev's high-spin gravity theories on four dimensional anti-de Sitter space. Maldacena and Zhiboedov showed that the high-spin symmetry determines the 2-point and 3-point functions of these theories at large N, up to two parameters. The duality to Vasiliev's gravity suggests that there is some mapping between the CS+scalar and CS+fermion theories (when one adds a quartic coupling to the scalar theories, to flow to their "critical fixed point"). We compute explicitly the large N limit of some 2-point and 3-point functions in these theories. We show that the results match with the general results of Maldacena and Zhiboedov, and they are consistent with an equivalence between the critical theory of N scalars coupled to a U(N) CS theory at level k, and the theory of k fermions coupled to a U(k) CS theory at level (N-1/2). We conjecture that this large N equivalence may be an exact duality between the scalar and fermion theories also at finite N, thus providing a bosonization of the fermionic theory. Similar results hold for real scalars (fermions) when U(N) is replaced by O(N).
Renormalization of Entanglement Entropy

Markus Luty University of California, Davis

March 12, 2013

PIRSA:13030108

High Energy Physics

The Standard Model Higgs boson may be mixed with another scalar that does not couple singly to gauge bosons or fermions. The electroweak quantum numbers of such an additional scalar can be determined by measuring the quartic Higgs-Higgs-vector-vector couplings, which contribute—along with the coveted triple Higgs coupling—to double Higgs production in e+e− collisions. We show that simultaneous sensitivity to the quartic Higgs-Higgs-vector-vector coupling and the triple Higgs coupling can be obtained using measurements of the double Higgs production cross section at two different e+e− center-of-mass energies. Kinematic distributions of the two Higgs bosons in the final state could provide additional discriminating power.
Effective field theory approach to quasi-single field inflation

Masahide Yamaguchi Tokyo Institute of Technology

March 12, 2013

PIRSA:13030096

Astrophysics

We apply the effective field theory approach to quasi-single field inflation, which contains an additional scalar field with Hubble scale mass other than inflaton. Based on the time-dependent spatial diffeomorphism, which is not broken by the time-dependent background evolution, the most generic action of quasi-single field inflation is constructed up to third order fluctuations. Using the obtained action, the effects of the additional massive scalar field on the primordial curvature perturbations are discussed. In particular, we calculate the power spectrum and discuss the momentum-dependence of three point functions in the squeezed limit for general settings of quasi-single field inflation. Our framework can be also applied to inflation models with heavy particles. We make a qualitative discussion on the effects of heavy particles during inflation and that of sharp turning trajectory in our framework.
Efficient Distributed Quantum Computing

Oliver Gray University of Bristol

March 11, 2013

PIRSA:13030104

Quantum Physics

I will explain how to simulate arbitrary quantum circuits on a distributed quantum computer (DQC), in which the pairs of qubits that are allowed to interact are restricted to the edges of some (connected) graph G. Even for graphs with only a modest number of long-range qubit interactions, such as the hypercube, this simulation is, in fact, efficient. Furthermore, for all graphs, the emulation scheme is very close to being optimal.
Secondly I will present an efficient quantum algorithm for parallel unrestricted memory look-up. As an application, I will show that the space-time trade off for Element Distinctness and Collision Finding can be improved.
Both results arise from applying the ideas of reversible sorting networks to quantum computing.
http://arxiv.org/abs/1207.2307
This is What a Scientist Looks Like

Sampa Bhadra York University

Natalia Toro Stanford University

Shohini Ghose Wilfrid Laurier University

March 08, 2013

PIRSA:13030086
One-photon and two-photon switching in graphene and optical nanomaterials

Mahi Singh Western University

March 08, 2013

PIRSA:13030094

Condensed Matter

In this talk we will discuss both the one-photon and two-photon switching mechanisms in hybrid nanomaterials made from two or more semiconductor, metallic and optical nanostructures. The most prominent examples of these nanostructures are graphene, semiconductor quantum dots, metallic nanoparticles, and photonic and polaritonic crystals. Advances in nanoscience have allowed for the construction of these new classes of hybrid nanomaterials. Optical excitations in semiconductor nanostructures are electron-hole pairs (excitons) whereas excitations in metallic nanostructures are surface plasmons which are collective oscillations of electrons. Therefore, the combination of these systems can provide attractive opportunities to modify, design and control optical properties and to observe new phenomena which are based on exciton-plasmon interactions. It is expected that this research will provide a theoretical road map for the development of optical sensing and optical switching.
The Effects of Limited Resources and Opportunities on Women’s Careers in Physics: Results from the Global Survey of Physicists

Rachel Ivie American Institute of Physics

March 08, 2013

PIRSA:13030082

The results of the Global Survey of Physicists draw attention to the need to focus on factors other than representation when discussing the situation of women in physics. Previous studies of women in physics have mostly focused on the lack of women in the field. This study goes beyond the obvious shortage of women and shows that there are much deeper issues. For the first time, a multinational study was conducted with 15000 respondents from 130 countries, showing that problems for women in physics transcend national borders. Across all countries, women have fewer resources and opportunities and are more affected by cultural expectations concerning child care. We show that limited resources and opportunities hurt career progress, and because women have fewer opportunities and resources, their careers progress more slowly. We also show the disproportionate effects of children on women physicists' careers. Cultural expectations about home and family are difficult to change. However, for women to have successful outcomes and advance in physics, they must have equal access to resources and opportunities. An article based on these findings can be found at: http://www.physicstoday.org/resource/1/phtoad/v65/i2/p47_s1

Title	Date	Collection	Type	Info
A CDT Hamiltonian from Horava-Lifshitz gravity	2013‑03‑14	Quantum Gravity	Scientific Series	View details
The dynamics of asymptotically anti-de Sitter spacetimes	2013‑03‑14	Strong Gravity	Scientific Series	View details
The Higgs confronts 3 universes at the LHC	2013‑03‑13	Colloquium	Scientific Series	View details
Advanced General Relativity - Lecture 15	2013‑03‑12	Elements of General Relativity	Course	View details
Neorealism and the Internal Language of Topoi	2013‑03‑12	Quantum Foundations	Scientific Series	View details
Large N Chern-Simons-matter theories and three dimensional bosonization	2013‑03‑12	Quantum Fields and Strings	Scientific Series	View details
Renormalization of Entanglement Entropy	2013‑03‑12	Particle Physics	Scientific Series	View details
Effective field theory approach to quasi-single field inflation	2013‑03‑12	Cosmology and Gravitation	Scientific Series	View details
Efficient Distributed Quantum Computing	2013‑03‑11	Perimeter Institute Quantum Discussions	Scientific Series	View details
This is What a Scientist Looks Like	2013‑03‑08	International Women's Day 2013	Conference	View details
One-photon and two-photon switching in graphene and optical nanomaterials	2013‑03‑08	Quantum Matter	Scientific Series	View details
The Effects of Limited Resources and Opportunities on Women’s Careers in Physics: Results from the Global Survey of Physicists	2013‑03‑08	International Women's Day 2013	Conference	View details

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Format results

A CDT Hamiltonian from Horava-Lifshitz gravity

The dynamics of asymptotically anti-de Sitter spacetimes

The Higgs confronts 3 universes at the LHC

Advanced General Relativity - Lecture 15

Neorealism and the Internal Language of Topoi

Large N Chern-Simons-matter theories and three dimensional bosonization

Renormalization of Entanglement Entropy

Effective field theory approach to quasi-single field inflation

Efficient Distributed Quantum Computing

This is What a Scientist Looks Like

One-photon and two-photon switching in graphene and optical nanomaterials

The Effects of Limited Resources and Opportunities on Women’s Careers in Physics: Results from the Global Survey of Physicists

A CDT Hamiltonian from Horava-Lifshitz gravity

The dynamics of asymptotically anti-de Sitter spacetimes

The Higgs confronts 3 universes at the LHC

Advanced General Relativity - Lecture 15

Neorealism and the Internal Language of Topoi

Large N Chern-Simons-matter theories and three dimensional bosonization

Renormalization of Entanglement Entropy

Effective field theory approach to quasi-single field inflation

Efficient Distributed Quantum Computing

This is What a Scientist Looks Like

One-photon and two-photon switching in graphene and optical nanomaterials

The Effects of Limited Resources and Opportunities on Women’s Careers in Physics: Results from the Global Survey of Physicists