News: 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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Research Highlights
Tue January 1, 2013

Collectively Enhanced Interactions in Solid-state Spin Qubits

We proposed and analyzed a technique to collectively enhance interactions between solid-state quantum registers composed from random networks of spin qubits. In such systems, disordered dipolar interactions generically result in localization. In our study, we demonstrated the emergence of a single collective delocalized eigenmode as one turned on a transverse field. The interaction strength between...
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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...
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Research Highlights
Tue January 1, 2013

Experimentally efficient methods for estimating the performance of quantum measurements

In this work we proposed metrics to characterize the performance of quantum measurements and provided experimentally accessible and efficient protocols to estimate these metrics. This work thus fills a gap in the characterization of quantum operations, which has until now focused on just the system evolution (via techniques such as quantum process tomography) providing a...
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Research Highlights
Tue January 1, 2013

Single-photon Nonlinear optics with Graphene Plasmons

We showed that it was possible to realize significant nonlinear optical interactions at the few photon level in graphene nanostructures. Our approach took advantage of the electric field enhancement associated with the strong confinement of graphene plasmons and the large intrinsic nonlinearity of graphene. Such a system could provide a powerful platform for quantum nonlinear...
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News type:
Research Highlights