News

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...
Read More »
News type:
Research Highlights
Tue January 1, 2013

Coherence and Raman Sideband Cooling of a Single Atom in an Optical Tweezer

We investigated quantum control of a single atom in a tightly focused optical tweezer trap. We showed that inevitable spatially varying polarization gave rise to significant internal-state decoherence but that the effect could be mitigated by an appropriately chosen magnetic bias field. That enabled Raman sideband cooling of a single atom close to its three-dimensional...
Read More »
News type:
Research Highlights
Tue January 1, 2013

A Quantum Network of Clocks

The development of precise atomic clocks has led to many scientific and technological advances that play an increasingly important role in modern society. Shared timing information constitutes a key resource for positioning and navigation with a direct correspondence between timing accuracy and precision in applications such as the Global Positioning System (GPS). By combining precision...
Read More »
News type:
Research Highlights
Tue January 1, 2013

Many-body Localization with Dipoles

Systems of strongly interacting dipoles offer an attractive platform to study many-body localized phases, owing to their long coherence times and strong interactions. We explored conditions under which such localized phases persisted in the presence of power-law interactions and supplemented our analytic treatment with numerical evidence of localized states in one dimension. We proposed several...
Read More »
News type:
Research Highlights
Tue January 1, 2013

Beyond Universal Long-Range van der Waals Interactions with Ultracold 6Li2 Molecules

We have found that collisional loss of ultracold 6Li2 molecules can be determined by physics beyond universal long-range van der Waals interactions [1]. Starting with a degenerate Fermi gas of 6Li produced by sympathetic cooling with bosonic 23Na, we form Li2 molecules by a magnetic field sweep around a narrow Feshbach resonance. The resulting molecules...
Read More »
News type:
Research Highlights
Tue January 1, 2013

Nanometer-scale Thermometry in a Living Cell

Sensitive probing of temperature variations on nanometre scales is an outstanding challenge in many areas of modern science and technology. In particular, a thermometer capable of subdegree temperature resolution over a large range of temperatures as well as integration within a living system could provide a powerful new tool in many areas of biological, physical...
Read More »
News type:
Research Highlights
Tue January 1, 2013

Keldysh Approach for Non-equilibrium Phase Transitions in Quantum Optics: Beyond the Dicke Model in Optical Cavities

We investigated nonequilibrium phase transitions for driven atomic ensembles interacting with a cavity mode and coupled to a Markovian dissipative bath. In the thermodynamic limit and at low frequencies, we showed that the distribution function of the photonic mode was thermal, with an effective temperature set by the atom-photon interaction strength. That behavior characterized the...
Read More »
News type:
Research Highlights
Tue January 1, 2013

Non-Equilibrium Fractional Quantum Hall State of Light

We investigated the quantum dynamics of systems, which involved small numbers of strongly interacting photons. Specifically, we developed an efficient method to investigate such systems when they were externally driven with a coherent field. Furthermore, we showed how to quantify the many-body quantum state of light via correlation functions. Finally, we applied that method to...
Read More »
News type:
Research Highlights
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...
Read More »
News type:
Research Highlights
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...
Read More »
News type:
Research Highlights