Scientific Series

Displaying 3073 - 3084 of 5110

Non local weak measurements

Aharon Brodutch Institute for Quantum Computing (IQC)
October 07, 2014

PIRSA:14100073
Quantum Foundations
On reducing 3d supersymmetric theories to two dimensions

Brian Willett Institute for Advanced Study (IAS)
October 07, 2014

PIRSA:14100005
Quantum Fields and Strings
De Sitter Wavefunctionals and the Resummation of Time

Matthew Baumgart Carnegie Mellon University
October 07, 2014

PIRSA:14100051
Particle Physics
Flux Compactifications Grow Lumps

Claire Zukowski University of California, Berkeley
October 07, 2014

PIRSA:14100081
Cosmology
Computer Algebra for Theoretical Physics

Edgardo Cheb-Terrab Maplesoft

October 07, 2014

PIRSA:14100068
Probing (beyond) general relativity with compact binaries and gravitational waves

Leo Stein Cornell University
October 02, 2014

PIRSA:14100003
Strong Gravity
The Effective Field Theory of Cosmological Large Scale Structures

Leonardo Senatore ETH Zurich
October 02, 2014

PIRSA:14090041
Cosmology
Defects: A new window into topological quantum matter

Maissam Barkeshli University of California, Santa Barbara

October 01, 2014

PIRSA:14100048
The Topology of Information Flow

Jamie Vicary University of Oxford

September 30, 2014

PIRSA:14090076
Irreversibility and Entanglement Spectrum Statistics in Quantum Circuits

Eduardo Mucciolo University of Central Florida
September 30, 2014

PIRSA:14090028
Condensed Matter
3d Gravity, Universality and Poincare Series

September 30, 2014

PIRSA:14090005
ADMX: The Axion Dark Matter Experiment

Gray Rybka University of Washington
September 30, 2014

PIRSA:14090067
Particle Physics

Non local weak measurements

Aharon Brodutch Institute for Quantum Computing (IQC)
October 07, 2014

PIRSA:14100073
Quantum Foundations
Weak measurement is increasingly acknowledged as an important theoretical and experimental tool. Weak values- the results of weak measurements- are often used to understand seemingly paradoxical quantum behavior. Until now however, it was not known how to perform a weak non-local measurement of a general operator. Such a procedure is necessary if we are to take the associated `weak values' seriously as a physical quantity. We propose a novel scheme for performing non-local weak measurement which is based on the principle of quantum erasure. This method can be used for a large class of observables including those related to Hardy's paradox.
On reducing 3d supersymmetric theories to two dimensions

Brian Willett Institute for Advanced Study (IAS)
October 07, 2014

PIRSA:14100005
Quantum Fields and Strings
We study the dimensional reduction of 3d QFTs with N=2 supersymmetry. In particular, we are interested in deriving dualities between 2d N=(2,2) theories starting from 3d dualities. Our main tool is the supersymmetric index, ie, the partition function on S^2 x S^1, which formally reduces to the partition function on S^2 as the radius of the circle goes to zero. There are various technical subtleties in this limit of the index which reflect physical subtleties in the reduction of the theories. We reproduce several known 2d N=(2,2) dualities and find evidence for some new ones.
De Sitter Wavefunctionals and the Resummation of Time

Matthew Baumgart Carnegie Mellon University
October 07, 2014

PIRSA:14100051
Particle Physics
The holographic RG of Anti-De Sitter gives a powerful clue about the underlying AdS/CFT correspondence. The question is whether similar hints can be found for the heretofore elusive holographic dual of De Sitter. The framework of stochastic inflation uses nonperturbative insight to tame bad behavior in the perturbation series of a massless scalar in DS at late times. Remarkably, this fully quantum system loses phase information in the leading approximation, but retains a probabilistic character and allows for a controlled prediction of late time Green's functions. Recasting this as a "resummation of time", we wish understand whether the distributions that result can be thought of as an attractive UV fixed point of a theory
living on a spacelike slice of DS. We derive stochastic inflation via the wavefunctional approach to Quantum Field Theory. This allows for the straightforward implementation of corrections to the original framework.
Flux Compactifications Grow Lumps

Claire Zukowski University of California, Berkeley
October 07, 2014

PIRSA:14100081
Cosmology
The simplest flux compactifications are highly symmetric—a q-form flux is wrapped uniformly around an extra-dimensional q-sphere. I will discuss a family of solutions that break the internal SO(q+1) symmetry of these solutions down to SO(q)×Z_2, and show that often at least one of them has lower vacuum energy, larger entropy, and is more stable than the symmetric solution. I will describe the phase diagram of lumpy solutions and provide an interpretation in terms of an effective potential. Finally, I will provide evidence that the perturbatively stable vacua have a non-perturbative instability to spontaneously sprout lumps; generically this new decay is exponentially faster than all other known decays of the model.
Computer Algebra for Theoretical Physics

Edgardo Cheb-Terrab Maplesoft

October 07, 2014

PIRSA:14100068

Generally speaking, physicists still experience that computing with paper and pencil is in most cases simpler than computing on a Computer Algebra worksheet. On the other hand, recent developments in the Maple system implemented most of the mathematical objects and mathematics used in theoretical physics computations, and dramatically approximated the notation used in the computer to the one used in paper and pencil, diminishing the learning gap and computer-syntax distraction to a strict minimum. In connection, in this talk the Physics project at Maplesoft is presented and the resulting Physics package illustrated tackling problems in classical and quantum mechanics, general relativity and field theory. In addition to the 10 a.m lecture, there will be a hands-on workshop at 1pm in the Alice Room. Feel free to join!
Probing (beyond) general relativity with compact binaries and gravitational waves

Leo Stein Cornell University
October 02, 2014

PIRSA:14100003
Strong Gravity
General relativity enjoys phenomenal success in agreeing with experiments and observations, but it must break down at some point. Astrophysics can give guidance for what type of theory may correct general relativity, if we know which phenomenology to look for. I will discuss the possible corrections to the structure of compact objects, the binary problem, and observations with pulsar timing and gravitational wave detection. These corrections are computed in specific effective theories, such as Einstein-dilaton-Gauss-Bonnet (EdGB) and dynamical Chern-Simons (dCS) gravity, and we may further generalize the common aspects of these theories to build a parametrized framework which captures a large number of effective field theories.
The Effective Field Theory of Cosmological Large Scale Structures

Leonardo Senatore ETH Zurich
October 02, 2014

PIRSA:14090041
Cosmology
The Effective Filed Theory of Large Scale Structures provides a novel framework to analytically compute the clustering of the Large Scale Structures in the weakly non-linear regime in a consistent and reliable way. The theory that describes the long wavelength fluctuations is obtained after integrating out the short distance modes and adding suitable operators that allow to correctly reconstruct the effect of short distance fluctuations at long distances. A few observables have been computed so far, and the results are extremely promising. I will discuss the formalism and the main results so far.
Defects: A new window into topological quantum matter

Maissam Barkeshli University of California, Santa Barbara

October 01, 2014

PIRSA:14100048

Topologically ordered states, such as the fractional quantum Hall (FQH) states, are quantum states of matter with various exotic properties, including quasiparticles with fractional quantum numbers and fractional statistics, and robust topology-dependent ground state degeneracies. In this talk, I will describe a new aspect of topological states: their extrinsic defects. These include extrinsically imposed point-like or line-like defects that couple to the topological properties of the state in non-trivial ways. The extrinsic point defects localize topologically protected "parafermion" zero modes, which generalize the notion of Majorana fermion zero modes, and provide a new direction for realizing non-Abelian quantum statistics and topological quantum computation. The line defects allow direct quantum mechanical coupling between electrons and fractionalized anyons, leading to new ways to probe fractionalization. After describing the conceptual framework, I will focus on a specific set of experimental proposals, using conventional bilayer FQH states, to detect parafermion zero modes and to directly observe the long-predicted topological ground state degeneracy of FQH states. In the end I will comment on other ways in which extrinsic defects provide a new window into fractionalization.
The Topology of Information Flow

Jamie Vicary University of Oxford

September 30, 2014

PIRSA:14090076

I will outline a new topological foundation for computation, and show how it gives rise to a unified treatment of classical encryption and quantum teleportation, and a strong classical model for many quantum phenomena. This work connects to some other interesting topics, including quantum field theory, classical combinatorics, thermodynamics, Morse theory and higher category theory, which I will introduce in an elementary way.
Irreversibility and Entanglement Spectrum Statistics in Quantum Circuits

Eduardo Mucciolo University of Central Florida
September 30, 2014

PIRSA:14090028
Condensed Matter
We show that for a system evolving unitarily under a stochastic quantum circuit, the notions of irreversibility, universality of computation, and entanglement are closely related. As the state of the system evolves from an initial product state, it becomes increasingly entangled until entanglement reaches a maximum. We define irreversibility as the failure to find a circuit that disentangles a maximally entangled state. We show that irreversibility occurs when maximally entangled states are generated with a quantum circuit formed by gates from a universal quantum computation set. We find that irreversibility is also associated to a Wigner-Dyson statistics in the fluctuations of spacings between adjacent eigenvalues of the system’s reduced density matrix. In contrast, when the system is evolved with a non-universal set of gates, the statistics of the entanglement spacing deviates from Wigner-Dyson and the disentangling algorithm succeeds. We discuss how these findings open a new way to characterize non-integrability in quantum systems.
3d Gravity, Universality and Poincare Series

September 30, 2014

PIRSA:14090005

Modular invariance plays an important role in the AdS3/CFT2 correspondence. Using modular invariance, I discuss under what conditions a 2d CFT shows a Hawking-Page phase transition in the large c limit, and what this implies for the range of validity of the Cardy formula and the universality of its spectrum. I will also discuss partition functions obtained by summing over the modular group, how their properties are compatible with their gravity interpretation, and briefly touch on implications for the existence of pure gravity.
ADMX: The Axion Dark Matter Experiment

Gray Rybka University of Washington
September 30, 2014

PIRSA:14090067
Particle Physics
Axions are an exceptionally well-motivated dark matter candidate in addition to being a consequence of the Peccei-Quinn solution to the strong CP problem. ADMX (Axion Dark Matter eXperiment) has recently been selected as the axion search for the US DOE Second-Generation Dark Matter Program. I will discuss the imminent upgrade of ADMX to a definitive search for micro-eV mass dark matter axions as well as the ongoing research and development of new technologies to expand the reach of ADMX to the entire plausible dark matter axion mass range.

Title	Speaker(s)	Date	Talk Type	Info link
Non local weak measurements	Aharon Brodutch	2014-10-07	Scientific Series	View details
On reducing 3d supersymmetric theories to two dimensions	Brian Willett	2014-10-07	Scientific Series	View details
De Sitter Wavefunctionals and the Resummation of Time	Matthew Baumgart	2014-10-07	Scientific Series	View details
Flux Compactifications Grow Lumps	Claire Zukowski	2014-10-07	Scientific Series	View details
Computer Algebra for Theoretical Physics	Edgardo Cheb-Terrab	2014-10-07	Scientific Series	View details
Probing (beyond) general relativity with compact binaries and gravitational waves	Leo Stein	2014-10-02	Scientific Series	View details
The Effective Field Theory of Cosmological Large Scale Structures	Leonardo Senatore	2014-10-02	Scientific Series	View details
Defects: A new window into topological quantum matter	Maissam Barkeshli	2014-10-01	Scientific Series	View details
The Topology of Information Flow	Jamie Vicary	2014-09-30	Scientific Series	View details
Irreversibility and Entanglement Spectrum Statistics in Quantum Circuits	Eduardo Mucciolo	2014-09-30	Scientific Series	View details
3d Gravity, Universality and Poincare Series		2014-09-30	Scientific Series	View details
ADMX: The Axion Dark Matter Experiment	Gray Rybka	2014-09-30	Scientific Series	View details

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