Spin Squeezing via One-Axis Twisting with Coherent Light

We propose a new method of spin squeezing of atomic spin, based on the interactions between atoms and off-resonant light which are known as paramagnetic Faraday rotation and fictitious magnetic field of light. Since the projection process, squeezed light, or special interactions among the atoms are not required in this method, it can be widely applied to many systems. The attainable range of the squeezing parameter is S^{-2/5}, where S is the total spin, which is limited by additional fluctuations imposed by coherent light and the spherical nature of the spin distribution.Comment: 4 pages,6 figure

Quantum information processing using strongly-dipolar coupled nuclear spins

Dipolar coupled homonuclear spins present challenging, yet useful systems for quantum information processing. In such systems, eigenbasis of the system Hamiltonian is the appropriate computational basis and coherent control can be achieved by specially designed strongly modulating pulses. In this letter we describe the first experimental implementation of the quantum algorithm for numerical gradient estimation on the eigenbasis of a four spin system.Comment: 5 pages, 5 figures, Accepted in PR

Steady-state large-eddy simulations of convective and stable urban Boundary layers

A comprehensive investigation is carried out to establish best practice guidelines for the modelling of statistically steady-state non-neutral urban boundary layers (UBL) using large-eddy simulation (LES). These steady-state simulations enable targeted studies under realistic non-neutral conditions without the complications associated with the inherently transient nature of the UBL. An extensive set of simulations of convective and stable conditions is carried out to determine which simplifications, volumetric forcings, and boundary conditions can be applied to replicate the mean and turbulent (variance and covariance) statistics of this intrinsically transient problem most faithfully. In addition, a new method is introduced in which a transient simulation can be ‘frozen’ into a steady state. It is found that non-neutral simulations have different requirements to their neutral counterparts. In convective conditions, capping the boundary-layer height h with the top of the modelled domain to h/5 and h/10 (which is common practice in neutral simulations) reduces the turbulent kinetic energy by as much as 61% and 44%, respectively. Consistent with the literature, we find that domain heights lz≥5|L| are necessary to reproduce the convective-boundary-layer dynamics, where L is the Obukhov length. In stably stratified situations, the use of a uniform momentum forcing systematically underestimates the mechanical generation of turbulence over the urban canopy layer, and therefore leads to misrepresentations of both the inner- and outer-layer dynamics. The new ‘frozen-transient’ method that is able to maintain a prescribed flow state (including entrainment at the boundary-layer top) is shown to work well in both stable and convective conditions. Guidelines are provided for future studies of the capped and uncapped convective and stable UBL

Factorizing Numbers with the Gauss Sum Technique: NMR Implementations

Several physics-based algorithms for factorizing large number were recently published. A notable recent one by Schleich et al. uses Gauss sums for distinguishing between factors and non-factors. We demonstrate two NMR techniques that evaluate Gauss sums and thus implement their algorithm. The first one is based on differential excitation of a single spin magnetization by a cascade of RF pulses. The second method is based on spatial averaging and selective refocusing of magnetization for Gauss sums corresponding to factors. All factors of 16637 and 52882363 are successfully obtained.Comment: 4 pages, 4 figures; Abstract and Conclusion are slightly modified. References added and formatted with Bibte

Cardiovascular complications of conventional and targeted adjuvant breast cancer therapy

Adjuvant therapy has improved the survival of women with early breast cancer (BC). Meta-analyses suggest that anthracycline-based regimens reduced the annual BC death rate by ∼40% in women below the age of 50 and 20% in older women. Novel agents designed to modulate abnormal growth factor signaling in and around the BC cell further increase patients' chances of survival. However, both conventional chemotherapeutic agents as well as some of the novel signaling inhibitors can induce important cardiovascular side-effects, potentially attenuating the progress made in recent years. The mechanism of cancer drug-induced cardiovascular complications varies greatly with some compounds inducing irreversible myocardial cell damage, while others lead to temporary cell dysfunction. The challenge of the future will be to prospectively discriminate between irreversible damage which can lead to progressive cardiovascular disease and reversible cardiovascular dysfunctions without further prognostic implications. Since adjuvant therapy for BC is potentially curative, emphasis must be placed on finding treatments combining maximum efficacy with the minimum of long-term side-effects in order to achieve survival with preserved quality of lif

Fictitious Magnetic Resonance by Quasi-Electrostatic Field

We propose a new kind of spin manipulation method using a {\it fictitious} magnetic field generated by a quasi-electrostatic field. The method can be applicable to every atom with electron spins and has distinct advantages of small photon scattering rate and local addressability. By using a $\rm{CO_2}$ laser as a quasi-electrostatic field, we have experimentally demonstrated the proposed method by observing the Rabi-oscillation of the ground state hyperfine spin F=1 of the cold $\rm{^{87}Rb}$ atoms and the Bose-Einstein condensate.Comment: 5 pages, 5 figure

Measurement of the spatial extent of inverse proximity in a Py/Nb/Py superconducting trilayer using low-energy muon-spin rotation

The authors acknowledge the financial support of the EPSRC (Grant No. EP/J01060X).Muon-spin rotation has been used to observe directly the spatial variation of the magnetic flux density near the ferromagnetic-superconducting interface in a permalloy-niobium trilayer. Above the superconducting transition temperature Tc the profile of the induced magnetic flux density within the niobium layer has been determined. Below Tc there is a significant reduction of the induced flux density, predominantly near the ferromagnetic-superconducting interfaces. We are uniquely able to determine the magnitude and spatial variation of this reduction in induced magnetization due to the presence of the Cooper pairs, yielding the magnitude and length scale associated with this phenomenon. Both are inconsistent with a simple Meissner screening and indicate the existence of another mechanism, the influence of which is localized within the vicinity of the ferromagnetic interface.Publisher PDFPeer reviewe