News: Research Highlights

Tue January 1, 2013

Unconventional Magnetism via Optical Pumping of Interacting Spin Systems

We considered strongly interacting systems of effective spins, subject to dissipative spin-flip processes associated with optical pumping. We predicted the existence of novel magnetic phases in the steady state of that system, which emerged due to the competition between coherent and dissipative processes. Specifically, for strongly anisotropic spin-spin interactions, we found ferromagnetic, antiferromagnetic, spin-densitywave, and...
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Research Highlights
Tue January 1, 2013

Spin-Orbit Suppression of Cold Inelastic Collisions of Aluminum and Helium

Cold collisions between atoms play a critical role in much of atomic physics, being responsible for few-body interactions, thermalization, trap loss and decoherence.  The development of a detailed understanding of collisions is therefore crucial to the continued expansion of the field into new atomic systems, an expansion that has already led to the discovery of...
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Research Highlights
Tue January 1, 2013

Realizing Fractional Chern Insulators in Dipolar Spin Systems

Strongly correlated quantum systems can exhibit exotic behavior controlled by topology. We predicted that the v = 1/2 fractional Chern insulator arose naturally in a two-dimensional array of driven, dipolar interacting spins. As a specific implementation, we analyzed how to prepare and detect synthetic gauge potentials for the rotational excitations of ultracold polar molecules trapped...
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Research Highlights
Tue January 1, 2013

Quantum Nonlinear Optics: Strongly Interacting Photons

Quantum-optics researchers have been trying to achieve strong inter­actions between individual photons for decades. These interactions constitute a fundamental tool toward the ultimate control of light fields “quantum by quantum.” They can be used to realize deterministic two-qubit optical gates for scalable quantum computing and to produce highly correlated states for high-precision measurements. Also, they...
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Research Highlights
Tue January 1, 2013

Robustness of Quantum Memories Based on Majorana Zero Modes

We analyzed the rate at which quantum information encoded in zero-energy Majorana modes was lost in the presence of perturbations. We showed that information could survive for times that scale exponentially with the size of the chain both in the presence of quenching and time-dependent quadratic dephasing perturbations, even when the latter had spectral components...
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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...
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Research Highlights
Tue January 1, 2013

Topologically Protected Quantum State Transfer in a Chiral Spin Liquid

Topology plays a central role in ensuring the robustness of a wide variety of physical phenomena. Notable examples range from the current-carrying edge states associated with the quantum Hall and the quantum spin Hall effects to topologically protected quantum memory and quantum logic operations. We proposed and analysed a topologically protected channel for the transfer...
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Research Highlights
Tue January 1, 2013

All-Optical Switch and Transistor Gated by One Stored Photon

In this paper we demonstrate an all-optical switch gated by one stored photon. Using an atomic ensemble trapped inside an optical cavity, we store a photon incident transverse to the cavity in the atomic ensemble, thereby changing the state of one atom. This atom then blocks the cavity for photons incident along the cavity axis....
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Research Highlights
Tue January 1, 2013

Polaronic Model of Two-level Systems in Amorphous Solids

While two-level systems (TLSs) are ubiqitous in solid state systems, microscopic understanding of their nature remains an outstanding problem. Conflicting phenomenological models are used to describe TLSs in seemingly similar materials when probed with different experimental techniques. Specifically, bulk measurements in amorphous solids have been interpreted using the model of a tunneling atom or group...
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Research Highlights
Tue January 1, 2013

Coupling of a Single Trapped Atom to a Nanoscale Optical Cavity

In this paper in collaboration with the Lukin group, we demonstrate for the first time deterministic coupling of a trapped atom to a nanophotonic resonator. For details see Lukin’s report.
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News type:
Research Highlights