Talks

10681 - 10692 of 16443 Results

Towards Universal Quantum Computation Out of Relativistic Motion of Particle Detectors

David Aasen
California Institute of Technology

June 25, 2012

PIRSA:12060049
Boundary Effects on Quantum Entanglement and its Dynamics in a Detector-Field System

June 25, 2012

PIRSA:12060074
Tripartite Entanglement, Svetlichny Inequalities, and Non-inertial Observers

Robert Mann
University of Waterloo

June 25, 2012

PIRSA:12060042
Geometric Discord in Non-Inertial Frames

Eric Brown
University of Chicago

June 25, 2012

PIRSA:12060058
Quantum Teleportation from Alice to Rob in Vacuum

Shih-Yuin Lin
National Changhua University of Education

June 25, 2012

PIRSA:12060047
Physical Results with Fermions in RQI

June 25, 2012

PIRSA:12060046
Entanglement of a Relativistic Field in the Vacuum State

Benni Reznik
Tel Aviv University

June 25, 2012

PIRSA:12060069

Quantum Fields and Strings
The Quest for Localization

Juan José León García
Instituto de Física Fundamental (IFF - CSIC)

June 25, 2012

PIRSA:12060044
PSI Graduation - 2012

June 23, 2012

PIRSA:12060081
A Journalist's Perspective on Science Media

Ivan Semeniuk
The Globe and Mail

June 20, 2012

PIRSA:12060017
Pyrochlore Material Yb_2Ti_2O_7: A Model Quantum Spin Ice

June 15, 2012

PIRSA:12060072

Condensed Matter
Looking for Quantum Gravity in the Space of Conformal Field Theories

Joao Penedones
L'Ecole Polytechnique Federale de Lausanne (EPFL)

June 13, 2012

PIRSA:12060005

Towards Universal Quantum Computation Out of Relativistic Motion of Particle Detectors

David Aasen
California Institute of Technology

June 25, 2012

PIRSA:12060049
Boundary Effects on Quantum Entanglement and its Dynamics in a Detector-Field System

June 25, 2012

PIRSA:12060074

We analyze an exactly solvable model consisting of an inertial Unruh-DeWitt detector which interacts linearly with a massless quantum field in Minkowski spacetime with a perfectly reflecting flat plane boundary. This model is related to proposed mirror-field superposition and relevant experiments in macroscopic quantum phenomena, as well as atomic fluctuation forces near a conducting surface. Firstly a coupled set of equations for the detector’s and the field’s Heisenberg operators are derived. After coarse graining the field, the dynamics of the detector’s internal degreeof freedom is described by a quantum Langevin equation, where the dissipation and noise kernels respectively correspond to the retarded Green’s functions and Hadamard elementary functions of the free quantum field in half space. We use the linear entropy as measures of entanglement between the detector and the quantum field under mirror reflection, then solve the early-time detector-fieldentanglement dynamics. At late times when the combined system is in a stationary state, we obtain exact expressions for the detector’s covariance matrix and show that the detector-field entanglement decreases for smaller separation between the detector and the mirror.We explain the behavior of detector-field entanglement qualitatively with the help of a detector’s mirror image, compare them with the case of two real detectors and explain the differences.
Tripartite Entanglement, Svetlichny Inequalities, and Non-inertial Observers

Robert Mann
University of Waterloo

June 25, 2012

PIRSA:12060042

I discuss the behaviour of bipartite and tripartite non-locality between fermionic entangled states shared by observers, one of whom uniformly accelerates. Although fermionic entanglement persists for arbitrarily large acceleration, the Bell/CHSH inequalities cannot be violated for sufficiently large but finite acceleration. However the Svetlichny inequality, which is a measure of genuine tripartite non-locality, can be violated for any finite value of the acceleration.
Geometric Discord in Non-Inertial Frames

Eric Brown
University of Chicago

June 25, 2012

PIRSA:12060058

I review the recent work performed on computing the geometric discord in non-inertial frames. We consider the well-known case of an inertially maximally entangled state shared by inertial Alice and non-inertial Robb. It is found that for high accelerations the geometric discord decays to a negligible amount; this is in stark contrast to the entropic definition of quantum discord which asymptotes to a finite value in the same limit. Such a result has two different implications: the first being that usable quantum correlations are more limited in this regime than previously thought and the second being that geometric discord may not be a sufficient measure of quantum correlations. I will discuss both of these perspectives.
Quantum Teleportation from Alice to Rob in Vacuum

Shih-Yuin Lin
National Changhua University of Education

June 25, 2012

PIRSA:12060047

We consider quantum teleportation of continuous variables in a relativistic system with the Unruh-DeWitt detectorscoupled to a common quantum field initially in the Minkowski vacuum. An unknown coherent state of an Unruh-DeWitt detector is teleported from one inertial agent (Alice) to an almost uniformly accelerated agent (Rob), using a detector pair initially entangled and shared by these two agents. Results for the averaged physical fidelity of quantum teleportation will be discussed.
Physical Results with Fermions in RQI

June 25, 2012

PIRSA:12060046

A number of works in the field of relativistic quantum information have been devoted to the study of entanglement on certain simple families of Unruh-mode entangled states in non-inertial frames. In the fermionic case remarkable results such as the survival of entanglement at infinite acceleration have been obtained. In this talk we will present and analyze some issues related to the anticommuting character of fermionic field operators, which have been overlooked in the past, sometimes leading to unphysical results. We provide a simple way of obtaining physical results, yielding interesting consequences such as convergence of field entanglement for different families of Unruh mode-entangled states in the infinite acceleration limit.
Entanglement of a Relativistic Field in the Vacuum State

Benni Reznik
Tel Aviv University

June 25, 2012

PIRSA:12060069

Quantum Fields and Strings

We discuss gedanken experiments for measuring local and non-local observables in QFT that
respect causality, and can by used to test the entanglement between two spatially distant regions in the vacuum. It is shown that the entanglement decays exponentially with the distance between the regions and does not vanish, in contrast to the case of lattice models. We discuss in this respect a possible mechanism which might explain this persistence effect, and a connection between the Reeh-Schlieder theorem and superoscillations.
The Quest for Localization

Juan José León García
Instituto de Física Fundamental (IFF - CSIC)

June 25, 2012

PIRSA:12060044

This talk aims to review the obstacles met in QFT to reach an appropriate definition for such a basic concept as localization. The anti-local character of the square root of the "- Laplace-Beltrami + mass^2" operator prevents the existence of localized states with a finite number of quanta. (Bosonic) quantum fields describe elementary excitations of an extended system whose ground state is the vacuum. No wonder, there is a complicated relationship between the cardinal (quantal) and continuous (spatial) sides of the theory. We will also analyze the roles (if any) played in RQI by the localized excitations of the vacuum.
PSI Graduation - 2012

June 23, 2012

PIRSA:12060081
A Journalist's Perspective on Science Media

Ivan Semeniuk
The Globe and Mail

June 20, 2012

PIRSA:12060017

TBA
Pyrochlore Material Yb_2Ti_2O_7: A Model Quantum Spin Ice

June 15, 2012

PIRSA:12060072

Condensed Matter

We discuss the thermodynamic properties of the model exchange quantum spin ice material Yb_2Ti_2O_7. Using exchange parameters recently determined from high-field neutron scattering measurements, we calculate the thermodynamic properties of this model system. We find very good agreement with the heat capacity, entropy and magnetization measurements on the materials. We show that, in the weak quantum regime, quantum fluctuations lead to the selection, within the spin-ice manifold, of a conventional ordered ground state. However, the excitations above the ground state and their dynamics remain highly non-trivial. They consist of weakly bound spinon-antispinon pairs separated by long strings. We present several pieces of indirect evidence that the low temperature phase transition observed in these materials is to this conventional ordered state.
Looking for Quantum Gravity in the Space of Conformal Field Theories

Joao Penedones
L'Ecole Polytechnique Federale de Lausanne (EPFL)

June 13, 2012

PIRSA:12060005

Conformal field theories have many applications ranging from continuous phase transitions in Statistical Mechanics to models of beyond the Standard Model physics in Particle Physics. In this talk, I will explain another remarkable application: some conformal field theories can be used to define and study Quantum Gravity. I will also try to give a brief summary of some of the main ideas being discussed at the conference "Back to the Bootstrap II".

Title	Date	Collection	Type	Info
Towards Universal Quantum Computation Out of Relativistic Motion of Particle Detectors	2012‑06‑25	Relativistic Quantum Information - 2012	Conference	View details
Boundary Effects on Quantum Entanglement and its Dynamics in a Detector-Field System	2012‑06‑25	Relativistic Quantum Information - 2012	Conference	View details
Tripartite Entanglement, Svetlichny Inequalities, and Non-inertial Observers	2012‑06‑25	Relativistic Quantum Information - 2012	Conference	View details
Geometric Discord in Non-Inertial Frames	2012‑06‑25	Relativistic Quantum Information - 2012	Conference	View details
Quantum Teleportation from Alice to Rob in Vacuum	2012‑06‑25	Relativistic Quantum Information - 2012	Conference	View details
Physical Results with Fermions in RQI	2012‑06‑25	Relativistic Quantum Information - 2012	Conference	View details
Entanglement of a Relativistic Field in the Vacuum State	2012‑06‑25	Relativistic Quantum Information - 2012	Conference	View details
The Quest for Localization	2012‑06‑25	Relativistic Quantum Information - 2012	Conference	View details
PSI Graduation - 2012	2012‑06‑23			View details
A Journalist's Perspective on Science Media	2012‑06‑20	Colloquium	Scientific Series	View details
Pyrochlore Material Yb_2Ti_2O_7: A Model Quantum Spin Ice	2012‑06‑15	Quantum Matter	Scientific Series	View details
Looking for Quantum Gravity in the Space of Conformal Field Theories	2012‑06‑13	Colloquium	Scientific Series	View details

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