News: Research Highlights

262 articles

Tue, January 1, 2013

Coupling of NV Centers to Photonic Crystal Nanobeams in Diamond

The realization of efficient optical interfaces for solid-state atom-like systems is an important problem in quantum science with potential applications in quantum communications and quantum information processing. We described and demonstrated a technique for coupling single nitrogen vacancy (NV) centers to suspended diamond photonic crystal cavities with quality factors up to 6000. Specifically, we presented...

News type: Research Highlights

Tue, January 1, 2013

Progress on Laser Cooling of CaF

The internal structure and the long-range dipole-dipole interactions of ultracold polar molecules open new avenues in studying physics such as the quantum simulation of strongly correlated Hamiltonians, ultracold controlled chemistry or precision measurements. At present, a reliable general method to produce an ultracold sample of molecules is desired, but not available. The goal of this...

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...

News type: Research Highlights

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...

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...

News type: Research Highlights

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...

News type: Research Highlights

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...

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...

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...

News type: Research Highlights

Tue, January 1, 2013

Heisenberg-limited Atom Clocks based on Entangled Qubits

We presented a quantum-enhanced atomic clock protocol based on groups of sequentially larger Greenberger-Horne-Zeilinger (GHZ) states, which achieved the best clock stability allowed by quantum theory up to a logarithmic correction. The simultaneous interrogation of the laser phase with such a cascade of GHZ states realized an incoherent version of the phase estimation algorithm that...

News type: Research Highlights