Scientific Series

Displaying 3397 - 3408 of 5007

Results and highlights from Planck

Kendrick Smith Perimeter Institute for Theoretical Physics
April 16, 2013

PIRSA:13040123
Astrophysics
Continuous-variable entanglement distillation and non-commutative central limit theorems

Earl Campbell University of Sheffield
April 15, 2013

PIRSA:13040122
Quantum Physics
Quantum causal dynamics without absolute space or time
April 11, 2013

PIRSA:13040083
General Relativity & Quantum Cosmology
Spinning black-hole binaries as gravitational and cosmological probes

Enrico Barausse SISSA International School for Advanced Studies
April 11, 2013

PIRSA:13040082
General Relativity & Quantum Cosmology
Large Scale Bayesian Inference in Cosmology

Jens Jasche Institut d'Astrophysique de Paris
April 11, 2013

PIRSA:13040119
Astrophysics
Topological insulator of bosons in 3d via dyon condensation and the statistical Witten effect.

Max Metlitski Massachusetts Institute of Technology (MIT) - Department of Physics
April 10, 2013

PIRSA:13040117
Condensed Matter
An infalling observer in AdS/CFT and the black hole information paradox

Kyriakos Papadodimas European Organization for Nuclear Research (CERN)
April 09, 2013

PIRSA:13040118
High Energy Physics
The Death Throes of Massive Stars: Supernovae, Black Holes, and Neutrinos

Evan O'Connor California Institute of Technology
April 09, 2013

PIRSA:13040120
Astrophysics
Classical and quantum circuit obfuscation with braids

Stephen Jordan National Institute of Standards & Technology
April 08, 2013

PIRSA:13040111
Quantum Physics
2D to 4D Correspondence: Towers of Kinks versus Towers of Monopoles
April 05, 2013

PIRSA:13040031
High Energy Physics
Fundamental Physics with Optically Levitated Dielectric Objects

Asimina Arvanitaki Perimeter Institute
April 04, 2013

PIRSA:13040114
General Relativity & Quantum Cosmology
Black holes as probes of fundamental physics

Vitor Cardoso Instituto Superior Tecnico - Departamento de Física
April 03, 2013

PIRSA:13040109
High Energy Physics

Astrophysics

Results and highlights from Planck

Kendrick Smith Perimeter Institute for Theoretical Physics
April 16, 2013

PIRSA:13040123
Astrophysics
Cosmological results from Planck, a third-generation satellite mission to measure the cosmic microwave background, have just been announced. These results improve constraints on essentially all cosmological parameters, and have implications for several preexisting sources of tension with the standard cosmological model, while also raising new puzzles. I will discuss these results and their significance, as well as the next steps forward.
Continuous-variable entanglement distillation and non-commutative central limit theorems

Earl Campbell University of Sheffield
April 15, 2013

PIRSA:13040122
Quantum Physics
Entanglement distillation transforms weakly entangled noisy states into highly entangled states, a primitive to be used in quantum repeater schemes and other protocols designed for quantum communication and key distribution. In this work, we present a comprehensive framework for continuous-variable entanglement distillation schemes that convert noisy non-Gaussian states into Gaussian ones in many iterations of the protocol. Instances of these protocols include the recursive Gaussifier protocol and the pumping Gaussifier protocol. The flexibility of these protocols give rise to several beneficial trade-offs related to success probabilities or memory requirements that can be adjusted to reflect experimental specifics. Despite these protocols involving measurements, we relate the convergence in this protocols to new instances of non-commutative central limit theorems. Implications of the findings for quantum repeater schemes are discussed.
Quantum causal dynamics without absolute space or time
April 11, 2013

PIRSA:13040083
General Relativity & Quantum Cosmology
I will describe a discrete model of spacetime which is quantum-mechanical, causal, and background free. The kinematics is described by networks whose vertices are labelled with arrows. These networks can be evolved forwards (or backwards) in time by using unitary replacement rules. The arrow structure permits one to define dynamics without using an absolute time parameter. Based on arXiv:1201.2489.
Spinning black-hole binaries as gravitational and cosmological probes

Enrico Barausse SISSA International School for Advanced Studies
April 11, 2013

PIRSA:13040082
General Relativity & Quantum Cosmology
Large Scale Bayesian Inference in Cosmology

Jens Jasche Institut d'Astrophysique de Paris
April 11, 2013

PIRSA:13040119
Astrophysics
Already the last decade has witnessed unprecedented progress in the collection of cosmological data. Presently proposed and designed future cosmological probes and surveys permit us to anticipate the upcoming avalanche of cosmological information during the next decades.
The increase of valuable observations needs to be accompanied with the development of efficient and accurate information processing technology in order to analyse and interpret this data. In particular, cosmography projects, aiming at studying the origin and inhomogeneous evolution of
the Universe, involve high dimensional inference methods. For example, 3d cosmological density and velocity field inference requires to explore on the order of 10^7 or more parameters. Consequently, such projects critically rely on state-of-the-art information processing techniques
and, nevertheless, are often on the verge of numerical feasibility with present day computational resources. For this reason, in this talk I will address the problem of high dimensional Bayesian inference from cosmological data sets, subject to a variety of statistical and systematic uncertainties. In particular, I will focus on the discussion of selected Markov Chain Monte Carlo techniques, permitting to efficiently solve inference problems with on the order of 10^7 parameters. Furthermore, these methods will be exemplified in various cosmological applications, raging from 3d non-linear density and photometric redshift inference to 4d physical state inference. These techniques permit us to exploit cosmologically relevant information from
observations to unprecedented detail and hence will significantly contribute to the era of precision cosmology.
Topological insulator of bosons in 3d via dyon condensation and the statistical Witten effect.

Max Metlitski Massachusetts Institute of Technology (MIT) - Department of Physics
April 10, 2013

PIRSA:13040117
Condensed Matter
In this talk, I will construct a symmetry protected topological phase of bosons in 3d with particle number conservation and time reversal symmetries, which is the direct bosonic analogue of the familiar electron topological insulator. The construction employs a parton decomposition of bosons, followed by condensation of parton-monopole composites. The surface of the resulting state supports a gapped symmetry respecting phase with intrinsic toric code topological order where both e and m anyons carry charge 1=2. It is well-known that one signature of the 3d electron topological insulator is the Witten eect: if the system is coupled to a compact electromagnetic gauge eld, a monopole in the bulk acquires a half-odd-integer polarization charge. I will discuss the corresponding phenomenon for the constructed topological insulator of bosons: a monopole can remain electrically neutral, but its statistics are transmuted from bosonic to fermionic. This \sta- tistical Witten eect" guarantees that the surface is either gapless, symmetry broken or carries an intrinsic topological order.
An infalling observer in AdS/CFT and the black hole information paradox

Kyriakos Papadodimas European Organization for Nuclear Research (CERN)
April 09, 2013

PIRSA:13040118
High Energy Physics
The Death Throes of Massive Stars: Supernovae, Black Holes, and Neutrinos

Evan O'Connor California Institute of Technology
April 09, 2013

PIRSA:13040120
Astrophysics
The endgame of massive star evolution is the gravitational-induced collapse of the central inert iron core. The collapse of the core continues until the matter reaches nuclear densities where the strong force between nucleons becomes dominant and provides sufficient pressure to stabilize the newly formed protoneutron star. What ensues is a complex multi-physics problem involving strong gravity, multidimensional hydrodynamic instabilities, magnetic fields, multispecies neutrino radiation, and supranuclear density physics to name a few.

We expect that most massive stars end this final stage of stellar evolution with a successful core-collapse supernova explosion. However, we also know that some of these core collapse events must fail and form stellar mass black holes.In his talk I will touch on two of the most important questions in core-collapse supernovae theory. I will briefly talk about what conditions are favourable for failed core-collapse supernovae (i.e. black hole formation). Conversely, I will discuss recent results from full three-dimensional, general-relativistic simulations of core-collapse and the implications for our understanding of the core-collapse supernova mechanism. If time permits, I'll discuss how neutrinos from the next galactic core-collapse supernova can help constrain properties of massive stars.
Classical and quantum circuit obfuscation with braids

Stephen Jordan National Institute of Standards & Technology
April 08, 2013

PIRSA:13040111
Quantum Physics
A circuit obfuscator is an algorithm that translates logic circuits into functionally-equivalent similarly-sized logic circuits that are hard to understand. While ad hoc obfuscators have been implemented, theoretical progress has mainly been limited to no-go results. In this work, we propose a new notion of circuit obfuscation, which we call partial indistinguishability. We then prove that, in contrast to previous definitions of obfuscation, partial indistinguishability obfuscation can be achieved by a polynomial-time algorithm. Specifically, our algorithm re-compiles the given circuit using a gate that satisfies the relations of the braid group, and then reduces to a braid normal form. Variants of our obfuscation algorithm can be applied to both classical and quantum circuits.
2D to 4D Correspondence: Towers of Kinks versus Towers of Monopoles
April 05, 2013

PIRSA:13040031
High Energy Physics
Two-dimensional models provide for a very attractive playground being a theory imitating some of the main features of QCD. Those include the asymptotic freedom, mass gap, confinement, chiral symmetry breaking and others. Furthermore, there is a correspondence between the spectra of four-dimensional SQCD and N=(2,2) CP(N-1) sigma model which was discovered more than a decade ago. This correspondence was explained later when it was found that SQCD supports non-Abelian strings with confined monopoles. The kinks of the two-dimensional theory are the monopoles attached to the strings. Thus, analysis of two-dimensional sigma models gives a deeper insight into the four-dimensional SQCD, in particular, into its strong dynamics.

We study the BPS spectrum of the N=(2,2) CP(N-1) model with the Z_N-symmetric twisted mass terms. We focus on analysis of the "extra'' towers of states found previously and compare them to the states that can be identified in the quasiclassical domain. Exact analysis of the strong-coupling states shows that not all of them survive when passing to the weak-coupling domain. Some of the states decay on the curves of the marginal stability (CMS). Thus, most of the strong coupling states do not exist at weak coupling and cannot be classified quasiclassically. This result lifts to four dimensions. In terms of the four-dimensional theory, the "extra" states are the strong coupling dyons, while the quasiclassical bound states are the bound states of dyons and quarks.
Fundamental Physics with Optically Levitated Dielectric Objects

Asimina Arvanitaki Perimeter Institute
April 04, 2013

PIRSA:13040114
General Relativity & Quantum Cosmology
In the past few years, optical cooling and manipulating of macroscopic objects, such as micro-mirrors and cantilevers has developed into an active field of research. In mechanical systems, the oscillator is attached to its suspension, a thermal contact that limits the motion isolation. On the other hand, when these small objects are levitated using the radiation pressure force of lasers, the excellent thermal isolation even at room temperatures helps produce very sensitive force detectors, and eventually quantum transducers for quantum computation purposes. These new techniques may have a variety of applications for fundamental physics such as short distance tests of gravity and gravitational wave detection at high frequencies. In addition, there are several proposals suggesting that optically levitated dielectrics can be cooled to the ground state of the center of mass motion, opening the exciting possibility of creating macroscopic matter-wave interferometers.
Black holes as probes of fundamental physics

Vitor Cardoso Instituto Superior Tecnico - Departamento de Física
April 03, 2013

PIRSA:13040109
High Energy Physics

Astrophysics
Black holes are the elementary particles of gravity, the final state of sufficiently massive stars and of energetic collisions. With a forty-year long history, black hole physics is a fully-blossomed field which promises to embrace several branches of theoretical physics. Here I review the main developments in highly dynamical black holes with an emphasis on high energy black hole collisions and probes of particle physics via superradiance.

Title	Speaker(s)	Date	Talk Type	Info link
Results and highlights from Planck	Kendrick Smith	2013-04-16	Scientific Series	View details
Continuous-variable entanglement distillation and non-commutative central limit theorems	Earl Campbell	2013-04-15	Scientific Series	View details
Quantum causal dynamics without absolute space or time		2013-04-11	Scientific Series	View details
Spinning black-hole binaries as gravitational and cosmological probes	Enrico Barausse	2013-04-11	Scientific Series	View details
Large Scale Bayesian Inference in Cosmology	Jens Jasche	2013-04-11	Scientific Series	View details
Topological insulator of bosons in 3d via dyon condensation and the statistical Witten effect.	Max Metlitski	2013-04-10	Scientific Series	View details
An infalling observer in AdS/CFT and the black hole information paradox	Kyriakos Papadodimas	2013-04-09	Scientific Series	View details
The Death Throes of Massive Stars: Supernovae, Black Holes, and Neutrinos	Evan O'Connor	2013-04-09	Scientific Series	View details
Classical and quantum circuit obfuscation with braids	Stephen Jordan	2013-04-08	Scientific Series	View details
2D to 4D Correspondence: Towers of Kinks versus Towers of Monopoles		2013-04-05	Scientific Series	View details
Fundamental Physics with Optically Levitated Dielectric Objects	Asimina Arvanitaki	2013-04-04	Scientific Series	View details
Black holes as probes of fundamental physics	Vitor Cardoso	2013-04-03	Scientific Series	View details

Supported by

Format results

Results and highlights from Planck

Continuous-variable entanglement distillation and non-commutative central limit theorems

Quantum causal dynamics without absolute space or time

Spinning black-hole binaries as gravitational and cosmological probes

Large Scale Bayesian Inference in Cosmology

Topological insulator of bosons in 3d via dyon condensation and the statistical Witten effect.

An infalling observer in AdS/CFT and the black hole information paradox

The Death Throes of Massive Stars: Supernovae, Black Holes, and Neutrinos

Classical and quantum circuit obfuscation with braids

2D to 4D Correspondence: Towers of Kinks versus Towers of Monopoles

Fundamental Physics with Optically Levitated Dielectric Objects

Black holes as probes of fundamental physics

Results and highlights from Planck

Continuous-variable entanglement distillation and non-commutative central limit theorems

Quantum causal dynamics without absolute space or time

Spinning black-hole binaries as gravitational and cosmological probes

Large Scale Bayesian Inference in Cosmology

Topological insulator of bosons in 3d via dyon condensation and the statistical Witten effect.

An infalling observer in AdS/CFT and the black hole information paradox

The Death Throes of Massive Stars: Supernovae, Black Holes, and Neutrinos

Classical and quantum circuit obfuscation with braids

2D to 4D Correspondence: Towers of Kinks versus Towers of Monopoles

Fundamental Physics with Optically Levitated Dielectric Objects

Black holes as probes of fundamental physics