Scientific Series

Displaying 3109 - 3120 of 5113

Monogamy of entanglement and improved mean-field ansatz for spin lattices

Ralf Schuetzhold Helmholtz-Zentrum Dresden-Rossendorf
September 02, 2014

PIRSA:14090069
Condensed Matter
Asymmetric Dark Matter Bound States

Mark Wise California Institute of Technology (Caltech)

September 02, 2014

PIRSA:14090068
Black hole evaporation without firewalls

James Bardeen
September 02, 2014

PIRSA:14090001
Cosmology
Coloron-assisted Leptoquarks at the LHC

Joshua Berger Cornell University
August 29, 2014

PIRSA:14080042
Particle Physics
The Gravity Dual of Supersymmetric Gauge Theories on a Squashed Five-Sphere

Martin Fluder University of Oxford

August 26, 2014

PIRSA:14080003
Testing QED with positronium state

Alexander Penin University of Alberta
August 26, 2014

PIRSA:14080038
Particle Physics
Classical statistics: resolving paradoxes since 1749

August 19, 2014

PIRSA:14080005
TBA

Senthil Todadri Massachusetts Institute of Technology (MIT) - Department of Physics
August 19, 2014

PIRSA:14080036
Condensed Matter
Towards construction of a Wightman QFT in four dimensions

Raimar Wulkenhaar Westfälische Wilhelms-Universität Münster

August 19, 2014

PIRSA:14080037
CMB anomalies from primordial gravitational waves

Yi Wang Hong Kong University of Science and Technology
August 13, 2014

PIRSA:14080019
Cosmology
Reconstructing quantum states from local data

Isaac Kim University of California, Davis
August 12, 2014

PIRSA:14080007
Condensed Matter
Algebraic Geometry in Cosmology

Matilde Marcolli University of Toronto
August 07, 2014

PIRSA:14080002
Cosmology

Monogamy of entanglement and improved mean-field ansatz for spin lattices

Ralf Schuetzhold Helmholtz-Zentrum Dresden-Rossendorf
September 02, 2014

PIRSA:14090069
Condensed Matter
We consider rather general spin-1/2 lattices with large coordination numbers Z.
Based on the monogamy of entanglement and other properties of the concurrence C,
we derive rigorous bounds for the entanglement between neighboring spins,
which show that C decreases for large Z. In addition, the concurrence C measures the deviation from mean-field behavior and can only vanish if the mean-field ansatz yields an exact ground state of the Hamiltonian. Motivated by these findings, we propose an improved mean-field ansatz by adding entanglement
Asymmetric Dark Matter Bound States

Mark Wise California Institute of Technology (Caltech)

September 02, 2014

PIRSA:14090068

One of the simplest low energy effective theories with Asymmetric Dark Matter contains a gauge singlet Dirac Fermion for the dark matter and a gauge singlet scalar as the mediator that the dark matter decays into. In this model I discuss the spectrum of bound states (two body and multi-body) and the cosmological production/dissociation of dark matter two body bound states.
Black hole evaporation without firewalls

James Bardeen
September 02, 2014

PIRSA:14090001
Cosmology
There need not be any conflict between unitarity, locality, and regularity of the horizon in black hole evaporation. I discuss a scenario in which the initial collapse that forms the black hole results in a small non-singular core inside an inner event horizon. This core grows as the result of quantum back-reaction associated with the increasing entanglement entropy of Hawking radiation quanta and their partners trapped inside the core. By the Page time the inner and outer apparent horizons either merge into a degenerate horizon, shutting off the Hawking radiation and leaving a massive remnant, or they disappear completely, allowing the trapped quantum information to escape. The scenario is justified by appeals to the Bousso covariant entropy bound and the ER=EPR conjecture. The talk is largely based on arxiv.org/1406.4098.
Coloron-assisted Leptoquarks at the LHC

Joshua Berger Cornell University
August 29, 2014

PIRSA:14080042
Particle Physics
Recent searches for a first-generation leptoquark by the CMS collaboration have shown around 2.5 sigma deviations from Standard Model predictions in both the eejj and e nu jj channels. Furthermore, the eejj invariant mass distribution has another 2.8 sigma excess from the CMS right-handed W plus heavy neutrino search. We point out that additional leptoquark production from a heavy coloron decay can provide a good explanation for all three excesses. The coloron has a mass around 2.1 TeV and the leptoquark mass can vary from 550 GeV to 650 GeV. A key prediction of this model is an edge in the total m_T distribution of e nu jj events at around 2.1 TeV.
The Gravity Dual of Supersymmetric Gauge Theories on a Squashed Five-Sphere

Martin Fluder University of Oxford

August 26, 2014

PIRSA:14080003

We construct the gravity duals of large N supersymmetric gauge theories on a squashed five-sphere. They are constructed in Euclidean Romans F(4) gauged supergravity in six-dimensions. We find a one- as well as a two-parameter family of solutions and evaluate the renormalised on-shell and fundamental string action for these solutions to find precise agreement with gauge theory.
Testing QED with positronium state

Alexander Penin University of Alberta
August 26, 2014

PIRSA:14080038
Particle Physics
The theory of quantum electrodynamics is recognized for the most accurate predictions in physics confirmed by experiment. I review the recent results on high precision tests of QED with an emphasize on the study of the positronium bound state.
Classical statistics: resolving paradoxes since 1749

August 19, 2014

PIRSA:14080005

There has been renewed interest in the effect that pre and postselection has on the foundations of quantum theory. Often, but not solely, in conjunction with weak measurement, pre and postselection scenarios are said to simultaneous create and resolve paradoxes. These paradoxes are said to be profound quandaries which bring us closer to the resolving the mysteries of the quantum. Here I was show that the same effects are present in classical physics when postselection and disturbance are allowed. In particular, I will demonstrate that anomalous weak values and protective measurements are already present in classical theory, thereby showing that these effects do not represent something uniquely quantum nor something that ought to be thought of as paradoxical. This is joint work with Josh Combes and Matt Leifer.
TBA

Senthil Todadri Massachusetts Institute of Technology (MIT) - Department of Physics
August 19, 2014

PIRSA:14080036
Condensed Matter
Towards construction of a Wightman QFT in four dimensions

Raimar Wulkenhaar Westfälische Wilhelms-Universität Münster

August 19, 2014

PIRSA:14080037

We prove that the $\lambda\phi^4_4$ quantum field theory on noncommutative Moyal space is, in the limit of infinite noncommutativity, exactly solvable in terms of the solution of a non-linear integral equation. The proof involves matrix model techniques which might be relevant for 2D quantum gravity and its generalisation to coloured tensor models of rank $\geq 3$. Surprisingly, our limit describes Schwinger functions of a Euclidean quantum field theory on standard $\mathbb{R}^4$ which satisfy the easy Osterwalder-Schrader axioms boundedness, covariance and symmetry. We prove that the decisive reflection positivity axiom is, for the 2-point function, equivalent to the question whether or not the solution of the integral equation is a Stieltjes function. The numerical solution of the integral equation leaves no doubt that this is true for coupling constants $\lambda\in[-0.39,0]$.
CMB anomalies from primordial gravitational waves

Yi Wang Hong Kong University of Science and Technology
August 13, 2014

PIRSA:14080019
Cosmology
We relate CMB anomalies and the recent observational evidence of primordial gravitational
waves. Two aspects are investigated:

(a) Several anomalies are spotted on the low ell temperature map of the WMAP and Planck
experiments. However, those anomalies disappear at high ell. We propose that those low ell
temperature anomalies may come from nearly scale invariant anomalies of the tensor sector.
Those anomalies on the temperature map naturally decay towards small scales, characterized
by the tensor-to-temperature radiation transfer function.

(b) The anomalies introduced by the gravitational waves discovery. Strong tension is noticed
between the BICEP2 and Planck data. We study in detail how blue tilt of the tensor spectrum
reconciles the tension between those datasets.
Reconstructing quantum states from local data

Isaac Kim University of California, Davis
August 12, 2014

PIRSA:14080007
Condensed Matter
We consider the problem of reconstructing global quantum states from local data. Because the reconstruction problem has many solutions in general, we consider the reconstructed state of maximum global entropy consistent with the local data. We show that unique ground states of local Hamiltonians are exactly reconstructed as the maximal entropy state. More generally, we show that if the state in question is a ground state of a local Hamiltonian with a degenerate space of locally indistinguishable ground states, then the maximal entropy state is close to the ground state projector. We also show that local reconstruction is possible for thermal states of local Hamiltonians. Finally, we discuss a procedure to certify that the reconstructed state is close to the true global state. We call the entropy of our reconstructed maximum entropy state the "reconstruction entropy", and we discuss its relation to emergent geometry in the context of holographic duality. This is a joint work with Brian Swingle.
Algebraic Geometry in Cosmology

Matilde Marcolli University of Toronto
August 07, 2014

PIRSA:14080002
Cosmology
The talk is based on joint work with Yuri Manin (arXiv:1402.2158). Using algebro-geometric blowups it is possible to construct a family of models of gluing of aeons across a Big-Bang type singularity, which includes the case of Penrose's conformally cyclic cosmology, as well as inflationary multiverse models generalizing the "eternal symmetree", and BKLL mixmaster type cosmologies. Using the mixmaster dynamics, formulated in terms of elliptic curves and modular curves, we speculate on the geometry of cosmological time near the gluing of aeons. We show also that this type of model allows for phenomena of noncommutativity of spacetime coordinates near the Big-Bang and the crossing of aeons.

Title	Speaker(s)	Date	Talk Type	Info link
Monogamy of entanglement and improved mean-field ansatz for spin lattices	Ralf Schuetzhold	2014-09-02	Scientific Series	View details
Asymmetric Dark Matter Bound States	Mark Wise	2014-09-02	Scientific Series	View details
Black hole evaporation without firewalls	James Bardeen	2014-09-02	Scientific Series	View details
Coloron-assisted Leptoquarks at the LHC	Joshua Berger	2014-08-29	Scientific Series	View details
The Gravity Dual of Supersymmetric Gauge Theories on a Squashed Five-Sphere	Martin Fluder	2014-08-26	Scientific Series	View details
Testing QED with positronium state	Alexander Penin	2014-08-26	Scientific Series	View details
Classical statistics: resolving paradoxes since 1749		2014-08-19	Scientific Series	View details
TBA	Senthil Todadri	2014-08-19	Scientific Series	View details
Towards construction of a Wightman QFT in four dimensions	Raimar Wulkenhaar	2014-08-19	Scientific Series	View details
CMB anomalies from primordial gravitational waves	Yi Wang	2014-08-13	Scientific Series	View details
Reconstructing quantum states from local data	Isaac Kim	2014-08-12	Scientific Series	View details
Algebraic Geometry in Cosmology	Matilde Marcolli	2014-08-07	Scientific Series	View details

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