Scientific Series

Displaying 3637 - 3648 of 5086

Warm Superconductors

Baskaran Ganapathy Institute of Mathematical Sciences

October 10, 2012

PIRSA:12100059
New Directions in Categorical Logic for Classical, Probabilistic and Quantum Physics

Tobias Fritz Universität Innsbruck
October 09, 2012

PIRSA:12100055
Mathematical Physics
AdS(3)/CFT(2) correspondence and integrability

Konstantin Zarembo Nordic Institute for Theoretical Physics
October 09, 2012

PIRSA:12100062
High Energy Physics

Mathematical Physics
Voids in the SDSS: from demography to cosmology

Paul Sutter Institut d'Astrophysique de Paris
October 09, 2012

PIRSA:12100041
Astrophysics
Scalars with Higher Derivatives in Supergravity and Cosmology

Jean-Luc Lehners Self Employed
October 09, 2012

PIRSA:12100042
Astrophysics
Testing Strong-Field General Relativity with Black Holes

Tim Johannsen

October 04, 2012

PIRSA:12100049
A Higgs but no sparticles yet: what it means for the (p)MSSM

Ahmed Ismail University of Pittsburgh
October 02, 2012

PIRSA:12100052
High Energy Physics
Homogeneous and Isotropic Universe from Nonlinear Massive Gravity

A. Emir Gumrukcuoglu
October 02, 2012

PIRSA:12100002
Astrophysics
New Observations about the Renormalization Group Flow

Zohar Komargodski Stony Brook University
September 26, 2012

PIRSA:12090058
High Energy Physics
Large-N Collective Fields and de Sitter / CFT correspondence

Sumit Das University of Kentucky
September 25, 2012

PIRSA:12090045
General Relativity & Quantum Cosmology

High Energy Physics
Supermassive black holes in non-spherical galactic nuclei and enhanced rates of star capture events

Eugene Vasiliev Rochester Institute of Technology
September 25, 2012

PIRSA:12090064
Astrophysics
A generalization of Kochen-Specker sets

Laura Mancinska Institute for Quantum Computing (IQC)

September 24, 2012

PIRSA:12090073

Warm Superconductors

Baskaran Ganapathy Institute of Mathematical Sciences

October 10, 2012

PIRSA:12100059
New Directions in Categorical Logic for Classical, Probabilistic and Quantum Physics

Tobias Fritz Universität Innsbruck
October 09, 2012

PIRSA:12100055
Mathematical Physics
I will give an idea of what category theory is and how it can be successfully applied in mathematics and the mathematical sciences by means of example. The example is a notion from mathematical logic formalizing the intuitive concept of "property". The new category-theoretical definition of this notion can physically be interpreted as a measurement. Unraveling this definition in particular categories can be regarded as defining the concept of "property" in different context, e.g. in classical, probabilistic and quantum physics, and in each case this recovers familiar things.
Disclaimer: Up to some differences in the technical details, all of this is work of Bart Jacobs. (See arXiv:1205.3940)
AdS(3)/CFT(2) correspondence and integrability

Konstantin Zarembo Nordic Institute for Theoretical Physics
October 09, 2012

PIRSA:12100062
High Energy Physics

Mathematical Physics
Integrability has been successfully used to compute the non-perturbative spectrum, Wilson loops and scattering amplitudes in the AdS/CFT correspondence. Most of these results apply to N=4, D=4 SYM / strings on AdS(5)xS(5). Strings on AdS(3)xM, where M is either S(3)xT(4) or S(3)xS(3)xS(1), are also integrable and potentially solvable by the same methods (Bethe ansatz, Y-system, TBA etc). An interesting aspect of string theory on AdS(3) is a large number of parameters that preserve integrability. One parameters, in particular, interpolates between the integrable RR AdS(3) background and conformal NSNS background described by a non-compact WZW model. Another interesting aspect of string theory on AdS(3) is emergence of target-space Viraroso symmetry. I will review how integrability arises in the AdS(3)/CFT(2) correspondence, and will describe what is (not) know about the Bethe ansatz solution of the relevant sigma-models.
Voids in the SDSS: from demography to cosmology

Paul Sutter Institut d'Astrophysique de Paris
October 09, 2012

PIRSA:12100041
Astrophysics
Cosmic voids are potentially a rich source of information for both astrophysics and cosmology. To enable such science, we produce the most comprehensive void catalog to date using the Sloan Digital Sky Survey Data Release 7 main sample out to redshift z = 0.2 and the Luminous Red Galaxy sample out to z = 0.44. Using a modified version of the parameter-free void finder ZOBOV, we fully take into account the presence of survey boundary and masks. We discuss basic catalog statistics such as number counts and redshift distributions, as well as describe some example data products derived from our catalog, such as radial density profiles and projected density maps. Using this catalog, we report on the first application of the Alcock-Paczynski test to stacked voids in spectroscopic redshift surveys by applying the shape-fitting procedure presented in Lavaux & Wandelt (2011) to ten void stacks out to redshift z = 0.36. Our results are consistent with WMAP 7-year cosmological constraints. We compare our results to alternate methods of constructing void stacks and comment on future observational prospects.
Scalars with Higher Derivatives in Supergravity and Cosmology

Jean-Luc Lehners Self Employed
October 09, 2012

PIRSA:12100042
Astrophysics
There are many situations in cosmology that motivate the study of scalar fields with higher-derivative actions. The best-known such situations are probably k-inflation (with DBI-inflation being a special case) and models based on galileon theories, but even eternal inflation and cyclic universes provide good reasons to study such theories. After an extended discussion of the motivations, I will show how scalar field theories with higher derivatives can be constructed in (minimal, 4-dimensional) supergravity, and will discuss their properties, especially in regard to their cosmological applications.
Testing Strong-Field General Relativity with Black Holes

Tim Johannsen

October 04, 2012

PIRSA:12100049
A Higgs but no sparticles yet: what it means for the (p)MSSM

Ahmed Ismail University of Pittsburgh
October 02, 2012

PIRSA:12100052
High Energy Physics
The phenomenological Minimal Supersymmetric Standard Model (pMSSM) provides a broad perspective on supersymmetric phenomenology. We have generated two large sets of pMSSM models with neutralino and gravitino LSPs, with sparticle masses extending up to 4 TeV. In this talk, I will discuss the implications of searches for supersymmetry and the Higgs, with particular attention to naturalness. In particular, we find that while sparticle spectra with moderately light stops are still allowed, such stops are difficult to find experimentally because of a wide array of possible cascade decays.
Homogeneous and Isotropic Universe from Nonlinear Massive Gravity

A. Emir Gumrukcuoglu
October 02, 2012

PIRSA:12100002
Astrophysics
The question of finite range gravity, or equivalently, whether graviton can have a non-zero mass, has been one of the major challenges in classical field theory for the last 70 years. Generically, a massive gravity theory contains an extra degree in addition to the 5 polarizations of massive graviton, which turns out to be a ghost. Recently, de Rham, Gabadadze and Tolley constructed a nonlinear theory of massive gravity, which successfully eliminates the ghost. Moreover, the theory has also phenomenological relevance, since the graviton mass may account for the accelerated expansion of the present universe, providing an alternative to dark energy. I will present self-accelerating cosmological solutions in the framework of this theory. The cosmological perturbations around these backgrounds have an interesting behavior: instead of the 5 degrees of freedom expected from a massive spin-2 field, only the 2 gravity wave polarizations are dynamical, at linear level. However, nonlinear analysis of the extra modes reveal the existence of ghost instabilities. This implies that a consistent universe solution in this theory should be inhomogeneous and/or anisotropic.
New Observations about the Renormalization Group Flow

Zohar Komargodski Stony Brook University
September 26, 2012

PIRSA:12090058
High Energy Physics
We review recent breakthroughs in understanding some general features of the Renormalization Group and of Quantum Field Theory. We discuss some applications of these new results and their deep connection to the entanglement of the Quantum Field Theory vacuum.
Large-N Collective Fields and de Sitter / CFT correspondence

Sumit Das University of Kentucky
September 25, 2012

PIRSA:12090045
General Relativity & Quantum Cosmology

High Energy Physics
We derive the collective theory of singlet fields of large-N Sp(N) spin models and display its unconventional features. Using the known relationship between O(N) collective fields and higher spin fields of Vasiliev theory in AdS space, we argue that the unique features of the Sp(N) collective theory suggest an interpretation in terms of a higher spin theory in de Sitter space, as proposed by Anninos, Hartman and Strominger. This is reminiscent of the way the Liouville mode is naturally interpreted as time in supercritical worldsheet string theory.
Supermassive black holes in non-spherical galactic nuclei and enhanced rates of star capture events

Eugene Vasiliev Rochester Institute of Technology
September 25, 2012

PIRSA:12090064
Astrophysics
We consider the stellar-dynamical processes which lead to the capture or tidal disruption of stars by a supermassive black hole, review the standard theory of two-body relaxation and loss-cone repopulation in spherical galactic nuclei, and extend it to the axisymmetric and triaxial nuclear star clusters. In the absense of symmetry which conserves angular momentum, the orbits of stars experience regular or chaotic changes of angular momentum even in the smooth potential of star cluster, which creates a substantial population of "centrophilic" orbits. We discuss the loss cone draining rates, i.e. rates of capture of stars from these orbits. Next we consider the relaxation phenomena in non-spherical nuclei, focusing on the differences between spherical, axisymmetric and triaxial cases. It turns out that the rates of repopulation of the loss cone are moderately higher in non-spherical systems, but in the triaxial case an additional, often substantial, increase of capture rates comes from draining of the centrophilic orbit population.
A generalization of Kochen-Specker sets

Laura Mancinska Institute for Quantum Computing (IQC)

September 24, 2012

PIRSA:12090073

I will discuss two generalizations of Kochen-Specker (KS) sets: projective KS sets and generalized KS sets. We will see that projective KS sets can be used to characterize all graphs for which the chromatic number is strictly larger than the quantum chromatic number. Here, the quantum chromatic number is defined via a nonlocal game based on graph coloring. We will further show that from any graph with separation between these two quantities, one can construct a classical channel for which entanglement assistance increases the one-shot zero-error capacity. As an example, we will consider a new family of classical channels with an exponential increase.

Title	Speaker(s)	Date	Talk Type	Info link
Warm Superconductors	Baskaran Ganapathy	2012-10-10	Scientific Series	View details
New Directions in Categorical Logic for Classical, Probabilistic and Quantum Physics	Tobias Fritz	2012-10-09	Scientific Series	View details
AdS(3)/CFT(2) correspondence and integrability	Konstantin Zarembo	2012-10-09	Scientific Series	View details
Voids in the SDSS: from demography to cosmology	Paul Sutter	2012-10-09	Scientific Series	View details
Scalars with Higher Derivatives in Supergravity and Cosmology	Jean-Luc Lehners	2012-10-09	Scientific Series	View details
Testing Strong-Field General Relativity with Black Holes	Tim Johannsen	2012-10-04	Scientific Series	View details
A Higgs but no sparticles yet: what it means for the (p)MSSM	Ahmed Ismail	2012-10-02	Scientific Series	View details
Homogeneous and Isotropic Universe from Nonlinear Massive Gravity	A. Emir Gumrukcuoglu	2012-10-02	Scientific Series	View details
New Observations about the Renormalization Group Flow	Zohar Komargodski	2012-09-26	Scientific Series	View details
Large-N Collective Fields and de Sitter / CFT correspondence	Sumit Das	2012-09-25	Scientific Series	View details
Supermassive black holes in non-spherical galactic nuclei and enhanced rates of star capture events	Eugene Vasiliev	2012-09-25	Scientific Series	View details
A generalization of Kochen-Specker sets	Laura Mancinska	2012-09-24	Scientific Series	View details

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Format results

Warm Superconductors

New Directions in Categorical Logic for Classical, Probabilistic and Quantum Physics

AdS(3)/CFT(2) correspondence and integrability

Voids in the SDSS: from demography to cosmology

Scalars with Higher Derivatives in Supergravity and Cosmology

Testing Strong-Field General Relativity with Black Holes

A Higgs but no sparticles yet: what it means for the (p)MSSM

Homogeneous and Isotropic Universe from Nonlinear Massive Gravity

New Observations about the Renormalization Group Flow

Large-N Collective Fields and de Sitter / CFT correspondence

Supermassive black holes in non-spherical galactic nuclei and enhanced rates of star capture events

A generalization of Kochen-Specker sets

Warm Superconductors

New Directions in Categorical Logic for Classical, Probabilistic and Quantum Physics

AdS(3)/CFT(2) correspondence and integrability

Voids in the SDSS: from demography to cosmology

Scalars with Higher Derivatives in Supergravity and Cosmology

Testing Strong-Field General Relativity with Black Holes

A Higgs but no sparticles yet: what it means for the (p)MSSM

Homogeneous and Isotropic Universe from Nonlinear Massive Gravity

New Observations about the Renormalization Group Flow

Large-N Collective Fields and de Sitter / CFT correspondence

Supermassive black holes in non-spherical galactic nuclei and enhanced rates of star capture events

A generalization of Kochen-Specker sets