Scientific Series

Displaying 3505 - 3516 of 5123

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

Ofer Aharony Weizmann Institute of Science
March 12, 2013

PIRSA:13030106
Quantum Fields and Strings
Renormalization of Entanglement Entropy

Markus Luty University of California, Davis
March 12, 2013

PIRSA:13030108
Particle Physics
Effective field theory approach to quasi-single field inflation

Masahide Yamaguchi Tokyo Institute of Technology
March 12, 2013

PIRSA:13030096
Cosmology
Efficient Distributed Quantum Computing

Oliver Gray University of Bristol
March 11, 2013

PIRSA:13030104
Quantum Information
One-photon and two-photon switching in graphene and optical nanomaterials

Mahi Singh Western University
March 08, 2013

PIRSA:13030094
Condensed Matter
Is the electron round?

Edward Hinds Imperial College London
March 08, 2013

PIRSA:13030100
Particle Physics
A Self-consistent Model of the Black Hole Evaporation

Yuki Yokokura RIKEN
March 07, 2013

PIRSA:13030093
Quantum Gravity
Rethinking Cosmology
March 06, 2013

PIRSA:13030079
Cosmology
Non-perturbative problems in gauge theories: N=2 quiver QCD

Vasily Pestun Institute for Advanced Study (IAS)
March 06, 2013

PIRSA:13030103
Quantum Fields and Strings
Thermodynamical Property of Entanglement Entropy for Excited States and Holographic Local Quench

Masahiro Nozaki University of Chicago
March 05, 2013

PIRSA:13030081
Quantum Fields and Strings
The correlator of two vector and one axial current in QCD

Kirill Melnikov Johns Hopkins University
March 05, 2013

PIRSA:13030099
Particle Physics
Getting the Most out of a Black Hole

Alexander Tchekhovskoy Princeton University
March 04, 2013

PIRSA:13030102
Cosmology

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

Ofer Aharony Weizmann Institute of Science
March 12, 2013

PIRSA:13030106
Quantum Fields and Strings
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
Particle 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
Cosmology
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 Information
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
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.
Is the electron round?

Edward Hinds Imperial College London
March 08, 2013

PIRSA:13030100
Particle Physics
We have made a new measurement of the electron’s electric dipole moment (EDM) using a beam of YbF molecules. By measuring atto-eV energy shifts in a molecule, this experiment probes new physics at the tera-eV energy scale. According to the standard model, this EDM is d_e=10^(-38) e.cm – some eleven orders of magnitude below the current experimental limit. However, most extensions to the standard model predict much larger values, potentially accessible to measurement . Hence, the search for the electron EDM is a search for physics beyond the standard model. I will describe our experimental method, our current results and their implications for particle physics. I will also outline the prospects for further major improvement in sensitivity.
A Self-consistent Model of the Black Hole Evaporation

Yuki Yokokura RIKEN
March 07, 2013

PIRSA:13030093
Quantum Gravity
We construct a self-consistent model which describes a black hole from formation to evaporation including the back reaction from the Hawking radiation. In the case where a null shell collapses, at the beginning the evaporation occurs, but it stops eventually, and a horizon and singularity appear. On the other hand, in the generic collapse process of a continuously distributed null matter, the black hole evaporates completely without forming a macroscopically large horizon nor singularity. We also find a stationary solution in the heat bath, which can be regarded as a normal thermodynamic object. (hep-th: 1302.4733)
Rethinking Cosmology
March 06, 2013

PIRSA:13030079
Cosmology
This talk will begin by discussing one by one the various reasons why cosmologists today consider the big bang inflationary cosmology to be the leading, if not proven, theory of the universe and then explaining why each of these reasons is flawed. This leads naturally to the question: what is the alternative? Understanding the flaws helps point the way.
Non-perturbative problems in gauge theories: N=2 quiver QCD

Vasily Pestun Institute for Advanced Study (IAS)
March 06, 2013

PIRSA:13030103
Quantum Fields and Strings
Non-perturbative effects are responsible for the essential dynamical features of the four-dimensional gauge theories such as QCD. The N=2 supersymmetric four-dimensional theories are an interesting class of models in which non-perturbative computations can be carried out with arbitrary precision using localization of the path integrals. I will explain the new exact non-perturbative results and the relation to classical and quantum integrable systems for a large class of N=2 supersymmetric QCD.
Thermodynamical Property of Entanglement Entropy for Excited States and Holographic Local Quench

Masahiro Nozaki University of Chicago
March 05, 2013

PIRSA:13030081
Quantum Fields and Strings
In this talk, we will describe our recent work. Recently, we focus on the thermodynamical property and time dependence of entanglement entropy. Using holography, we found that the entanglement entropy for a very small subsystem obeys a property which is analogous to the first law of thermodynamics when we excite the system. In relativistic setups, its effective temperature is proportional to the inverse of the subsystem size. This provides a universal relationship between the energy and the amount of quantum information. Moreover, we will propose a new holographic model of local quench and describe some results which we got by using this model. This talk is based on arXiv:1212.1164 [hep-th] and arXiv:1302.5703 [hep-th].
The correlator of two vector and one axial current in QCD

Kirill Melnikov Johns Hopkins University
March 05, 2013

PIRSA:13030099
Particle Physics
It is known that the correlator of one axial and two vector currents, that receives leading contributions through one-loop fermion triangle diagrams, is not modified by QCD radiative corrections at two loops. It was suggested that this non-renormalization of the VVA correlator persists in higher orders in perturbative QCD as well. To check this assertion, I compute the three-loop QCD corrections to the VAA-correlator using the technique of asymptotic expansions. I find that these corrections do not vanish and that they are proportional to the QCD beta-function. I will also review some properties of the VVA correlator that were discovered in recent years.
Getting the Most out of a Black Hole

Alexander Tchekhovskoy Princeton University
March 04, 2013

PIRSA:13030102
Cosmology
As black holes accrete surrounding gas, they often produce relativistic, collimated outflows, or jets. Jets are expected to form in the black hole vicinity making them powerful probes of strong-field gravity. However, how jet properties are connected to black hole and accretion flow properties has been unclear. Recent progress in computer simulations of black hole accretion enables studies of jet formation in unprecedented detail. For the first time, 3D general relativistic magnetohydrodynamic numerical simulations allow one to determine the maximum efficiency with which accretion onto black holes can power relativistic jets. I will present the dependence of this maximum efficiency on black hole spin and discuss how this dependence allows one to probe strong-field gravity. In realistic astrophysical systems, the angular momentum vector of the accretion flow can be tilted relative to the spin of the black hole. I will present the first simulations of jets from such tilted accretion systems and discuss their observational signatures.

Title	Speaker(s)	Date	Talk Type	Info link
Large N Chern-Simons-matter theories and three dimensional bosonization	Ofer Aharony	2013-03-12	Scientific Series	View details
Renormalization of Entanglement Entropy	Markus Luty	2013-03-12	Scientific Series	View details
Effective field theory approach to quasi-single field inflation	Masahide Yamaguchi	2013-03-12	Scientific Series	View details
Efficient Distributed Quantum Computing	Oliver Gray	2013-03-11	Scientific Series	View details
One-photon and two-photon switching in graphene and optical nanomaterials	Mahi Singh	2013-03-08	Scientific Series	View details
Is the electron round?	Edward Hinds	2013-03-08	Scientific Series	View details
A Self-consistent Model of the Black Hole Evaporation	Yuki Yokokura	2013-03-07	Scientific Series	View details
Rethinking Cosmology		2013-03-06	Scientific Series	View details
Non-perturbative problems in gauge theories: N=2 quiver QCD	Vasily Pestun	2013-03-06	Scientific Series	View details
Thermodynamical Property of Entanglement Entropy for Excited States and Holographic Local Quench	Masahiro Nozaki	2013-03-05	Scientific Series	View details
The correlator of two vector and one axial current in QCD	Kirill Melnikov	2013-03-05	Scientific Series	View details
Getting the Most out of a Black Hole	Alexander Tchekhovskoy	2013-03-04	Scientific Series	View details

Scientific Series

Format results