Quantum Computation

It’s high-NOON for five photons

Summary: 

Entanglement technique could boost quantum metrology

Physicists in Israel are the first to entangle five photons in a NOON state – the superposition of two extreme quantum states. Unlike previous schemes for creating such states, the researchers claim that their new technique can entangle an arbitrarily large number of photons – so called "high-NOON states". This could be good news for those developing quantum metrology techniques because high-NOON states could be used to improve the precision of a range of different measurements.

Ultracold dipoles are under control

Summary: 

Long-range interactions are a first

Physicists in the US have created an ultracold gas of molecules with "adjustable" dipole moments. The experiment, which is the first to study the effect of long-range dipole interactions in an ultracold gas, could lead to new ways of using trapped molecules to simulate quantum effects that occur in solids.

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Optical control of the refractive index of a single atom

Date: 
2010-04-29
Reference: 

Tobias Kampschulte, Wolfgang Alt, Stefan Brakhane, Martin Eckstein, René Reimann, Artur Widera, Dieter Meschede
Phys. Rev. Lett. 105, 153603 (2010)

The optical properties of an atomic medium can be changed dramatically by the coherent interaction with a near-resonant control light field: An optically dense medium can be rendered transparent and group velocities can be strongly reduced. So far the demonstration of this electromagnetically induced transparency (EIT) has relied on macroscopic ensembles of atoms probed by relatively intense light fields. Here we demonstrate the most elementary case, where the medium is formed by a single atom inside an optical cavity, probed by single photons.

Beyond standard Optical lattices

Date: 
2010-09-13 - 2010-12-10
Place: 
Kvali Institute for Theoretical Physics (University of Santa Barbara, California)

The aim of the workshop is to explore how experiments with ultracold gases can address key open problems in many-body quantum physics. Among other things it will focus on the following topics: fundamental limitations and new ideas in quantum simulation of unsolved models such as the Hubbard model; novel cooling schemes based on ideas from quantum information as well as atomic and many-body physics; emergent phenomena in non-equilibrium quantum dynamics; novel quantum magnetism in Bose and Fermi systems; realizing and probing topologically ordered states.

Electromagnetically induced transparency with single atoms in a cavity

Date: 
2010-06-10
Author(s): 

Martin Mücke, Eden Figueroa, Joerg Bochmann, Carolin Hahn, Karim Murr, Stephan Ritter, Celso J. Villas-Boas, Gerhard Rempe

Reference: 

Nature 465, 755 (2010)

Optical nonlinearities offer unique possibilities for the control of light with light. A prominent example is electromagnetically induced transparency (EIT) where the transmission of a probe beam through an optically dense medium is manipulated by means of a control beam. Scaling such experiments into the quantum domain with one, or just a few particles of both light and matter will allow for the implementation of quantum computing protocols with atoms and photons or the realisation of strongly interacting photon gases exhibiting quantum phase transitions of light.

First CHIST-ERA Conference

Date: 
2010-05-27 - 2010-05-28
Place: 
EUR - Rome

The purpose of this first CHIST-ERA conference will be to bring together personalities and scientists from the community of the call topics (Quantum Information Foundations and Technologies and Self-Awareness & Self-Consciousness) preliminarily chosen by the CHIST-ERA Consortium and that will be called for in the first CHIST-ERA transnational call for projects.

Single atoms go transparent

Summary: 

Electromagnetic Induced Transparency (EIT) seen in single atoms, real and artificial

Making an opaque material transparent might seem like magic. But for well over a decade, physicists have been able to do just that in atomic gases using the phenomenon of electromagnetically induced transparency (EIT). Now, however, this seemingly magical effect has been observed in single atoms – and in "artificial" atoms consisting of a superconducting loop – for the first time.

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Quantum Information, University of Leeds

Research Type: 
Theory
Experiment
  • Quantum Information Theory and Computation (Beige, Dunningham, Kendon, Pachos, Spiller)
  • Foundations of Quantum Mechanics (Dunningham, Beige, Spiller)
  • Optical and Solid State Implementations (Beige, Pachos, Spiller)
  • Bose Einstein Condensation (Dunningham, Pachos, Spiller)
  • Topological Quantum Computation (Pachos)
  • Quantum Simulations and Transport (Kendon)
  • Quantum Cryptography (Razavi, Spiller, Beige)
  • Quantum Communication Networks (Razavi)
Leader: 
Tim Spiller
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