News: Research Highlights

Wed January 1, 2014

Quantum Interference Between Independent Reservoirs in Open Quantum Systems

When a quantum system interacts with multiple reservoirs, the environmental effects are usually treated in an additive manner. We showed that that assumption breaks down for non-Markovian environments that have finite memory times. Specifically, we demonstrated that quantum interferences between independent environments could qualitatively modify the dynamics of the physical system. We illustrated that effect...
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Wed January 1, 2014

Buffer-gas loaded magneto-optical traps for Yb, Tm, Er, and Ho

Novel physics in areas like quantum information, cold controlled chemistry and precision measurements is predicted to be accessible with molecules at temperatures in the mK regime. These approaches require molecular beam sources which are unavailable at present. In particular, providing cold, slow and bright beams of a general set of molecules, ideally independent of their...
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Wed January 1, 2014

Quantum Nanophotonic Phase Switch with a Single Atom

In analogy to transistors in classical electronic circuits, a quantum optical switch is an important element of quantum circuits and quantum networks. Operated at the fundamental limit where a single quantum of light or matter controls another field or material system, it may enable fascinating applications such as long-distance quantum communication, distributed quantum information processing and...
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Tue January 1, 2013

All-optical Sensing of a Single-molecule Electron Spin

We demonstrated an all-optical method for magnetic sensing of individual molecules in ambient conditions at room temperature. Our approach was based on shallow nitrogen-vacancy (NV) centers near the surface of a diamond crystal, which we used to detect single paramagnetic molecules covalently attached to the diamond surface. The manipulation and readout of the NV centers...
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Tue January 1, 2013

Quantum Logic between Remote Quantum Registers

We considered two approaches to dark-spin-mediated quantum computing in hybrid solid-state spin architectures. First, we reviewed the notion of eigenmode-mediated unpolarized spin-chain state transfer and extended the analysis to various experimentally relevant imperfections: quenched disorder, dynamical decoherence, and uncompensated long-range coupling. In finite-length chains, the interplay between disorder-induced localization and decoherence yielded a natural optimal...
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Tue January 1, 2013

Dissipative Preparation of Spin Squeezed Atomic Ensembles in a Steady State

We presented and analyzed an approach for the generation of atomic spin-squeezed states. Our method involved the collective coupling of an atomic ensemble to a decaying mode of an open optical cavity. We demonstrated the existence of a collective atomic dark state, decoupled from the radiation field. Through the explicit construction of that state we...
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Tue January 1, 2013

Attractive Photons in a Quantum Nonlinear Medium

In this paper, we demonstrate for the first time a bound state of two photons. We illuminate a dense and cold atomic ensemble with weak laser light underconditions of electromagnetically induced transparency to an atomic Rydberg state. When we detune the control laser coupling the unstable intermediate state to the Rydberg level, the probe photons...
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Tue January 1, 2013

Single-photon Nonlinearities in Two-mode Optomechanics

We presented a detailed theoretical analysis of a weakly driven, multimode optomechanical system, in which two optical modes were strongly and near-resonantly coupled to a single mechanical mode via a three-wave mixing interaction. We calculated one- and two-time intensity correlations of the two optical fields and compared them to analogous correlations in atom-cavity systems. Nonclassical...
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