Quantum Information Processing with Delocalized Qubits under Global Control

Any technology for quantum information processing (QIP) must embody within it quantum bits (qubits) and maintain control of their key quantum properties of superposition and entanglement. Typical QIP schemes envisage an array of physical systems, such as electrons or nuclei, with each system representing a given qubit. For adequate control, systems must be distinguishable either by physical separation or unique frequencies, and their mutual interactions must be individually manipulable. These difficult requirements exclude many nanoscale technologies where systems are densely packed and continuously interacting. Here we demonstrate a new paradigm: restricting ourselves to global control pulses we permit systems to interact freely and continuously, with the consequence that qubits can become delocalized over the entire device. We realize this using NMR studies of three carbon-13 nuclei in alanine, demonstrating all the key aspects including a quantum mirror, one- and two-qubit gates, permutation of densely packed qubits and Deutsch algorithms.Comment: 4 pages, 5 figure

WASP-12b as a prolate, inflated and disrupting planet from tidal dissipation

The class of exotic Jupiter-mass planets that orbit very close to their parent stars were not explicitly expected before their discovery. The recently found transiting planet WASP-12b has a mass Mp = 1.4(+/-0.1) Jupiter masses (MJ), a mean orbital distance of only 3.1 stellar radii (meaning it is subject to intense tidal forces), and a period of 1.1 days. Its radius 1.79(+/- 0.09) RJ is unexpectedly large and its orbital eccentricity 0.049(+/-0:015) is even more surprising as such close orbits are in general quickly circularized. Here we report an analysis of its properties, which reveals that the planet is losing mass to its host star at a rate ~ 10^-7 MJ yr^-1. The planets surface is distorted by the stars gravity and the light curve produced by its prolate shape will differ by about ten per cent from that of a spherical planet. We conclude that dissipation of the stars tidal perturbation in the planets convective envelope provides the energy source for its large volume. We predict up to 10mJy CO band-head (2.292 micron) emission from a tenuous disk around the host star, made up of tidally stripped planetary gas. It may also contain a detectable resonant super-Earth, as a hypothetical perturber that continually stirs up WASP-12b's eccentricity.Comment: Accepted to Nature, 14 pages, 1 figur

Empiric Treatment for Suspected Malaria in the United States: A Case Report.

Malaria in the United States is rare and most commonly presents among returning travelers from endemic areas. Diagnosis is classically dependent on a positive blood smear or polymerase chain reaction (PCR) test. The objective of this case report is to highlight a case of suspected malaria in a high-risk individual with negative diagnostic testing where a trial of empiric treatment was initiated based on clinical presentation after a thorough discussion of risks and benefits. However, empiric treatment based on a single case is limiting. We present a case of a 56-year-old man with extensive travel history throughout Asia, who presented after multiple episodes of unprovoked 24-hour fevers over the past seven years. A thorough rheumatologic and infectious inpatient workup was negative and oncology was consulted with low suspicion for malignancy. However, based on clinical presentation and history, malaria remained highly suspected and an empiric trial of anti-malarial treatment was initiated. One year after receiving treatment, the patient has not experienced any further febrile episodes. The efficacy of blood smears and PCR may be influenced by the malarial strain, as some species have low circulating biomass. Therefore, blood smears and PCR testing may not always be diagnostic. Clinical signs supportive of a malarial infection include fever, rigors, chills, hepato/splenomegaly, hyperbilirubinemia, and thrombocytopenia. Malaria is endemic to many regions outside of Africa, including Asia, and should be considered in any returning traveler with recurrent fevers

High-Q-factor Al [subscript 2]O[subscript 3] micro-trench cavities integrated with silicon nitride waveguides on silicon

We report on the design and performance of high-Q integrated optical micro-trench cavities on silicon. The microcavities are co-integrated with silicon nitride bus waveguides and fabricated using wafer-scale silicon-photonics-compatible processing steps. The amorphous aluminum oxide resonator material is deposited via sputtering in a single straightforward post-processing step. We examine the theoretical and experimental optical properties of the aluminum oxide micro-trench cavities for different bend radii, film thicknesses and near-infrared wavelengths and demonstrate experimental Q factors of > 10[superscript 6]. We propose that this high-Q micro-trench cavity design can be applied to incorporate a wide variety of novel microcavity materials, including rare-earth-doped films for microlasers, into wafer-scale silicon photonics platforms

Thermal expansion and elastic anisotropy in single crystal Al2O3 and SiC reinforcements

In single crystal form, SiC and Al2O3 are attractive reinforcing components for high temperature composites. In this study, the axial coefficients of thermal expansion and single crystal elastic constants of SiC and Al2O3 were used to determine their coefficients of thermal expansion and Young's moduli as a function of crystallographic orientation and temperature. SiC and Al2O3 exhibit a strong variation of Young's modulus with orientation; however, their moduli and anisotropies are weak functions of temperature below 1000 C. The coefficients of thermal expansion exhibit significant temperature dependence, and that of the non-cubic Al2O3 is also a function of crystallographic orientation

Gravitational waves from intermediate-mass-ratio inspirals for ground-based detectors

We explore the prospects for Advanced LIGO to detect gravitational waves from neutron stars and stellar mass black holes spiraling into intermediate-mass ($M\sim 50 M_\odot$ to $350 M_\odot$) black holes. We estimate an event rate for such \emph{intermediate-mass-ratio inspirals} (IMRIs) of up to $\sim 10$--$30 \mathrm{yr}^{-1}$. Our numerical simulations show that if the central body is not a black hole but its metric is stationary, axisymmetric, reflection symmetric and asymptotically flat then the waves will likely be tri-periodic, as for a black hole. We report generalizations of a theorem due to Ryan (1995) which suggest that the evolutions of the waves' three fundamental frequencies and of the complex amplitudes of their spectral components encode (in principle) a full map of the central body's metric, full details of the energy and angular momentum exchange between the central body and the orbit, and the time-evolving orbital elements. We estimate that Advanced LIGO can measure or constrain deviations of the central body from a Kerr black hole with modest but interesting accuracy.Comment: Accepted for publication in Physical Review Letter