891 research outputs found

    Engineering the Dynamics of Effective Spin-Chain Models for Strongly Interacting Atomic Gases

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    We consider a one-dimensional gas of cold atoms with strong contact interactions and construct an effective spin-chain Hamiltonian for a two-component system. The resulting Heisenberg spin model can be engineered by manipulating the shape of the external confining potential of the atomic gas. We find that bosonic atoms offer more flexibility for tuning independently the parameters of the spin Hamiltonian through interatomic (intra-species) interaction which is absent for fermions due to the Pauli exclusion principle. Our formalism can have important implications for control and manipulation of the dynamics of few- and many-body quantum systems; as an illustrative example relevant to quantum computation and communication, we consider state transfer in the simplest non-trivial system of four particles representing exchange-coupled qubits.Comment: 10 pages including appendix, 3 figures, revised versio

    Scalable solid-state quantum processor using subradiant two-atom states

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    We propose a realization of a scalable, high-performance quantum processor whose qubits are represented by the ground and subradiant states of effective dimers formed by pairs of two-level systems coupled by resonant dipole-dipole interaction. The dimers are implanted in low-temperature solid host material at controllable nanoscale separations. The two-qubit entanglement either relies on the coherent excitation exchange between the dimers or is mediated by external laser fields.Comment: 4 pages, 3 figure

    Anomalous latent heat in non-equilibrium phase transitions

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    We study first-order phase transitions in a two-temperature system, where due to the time-scale separation all the basic thermodynamical quantities (free energy, entropy, etc) are well-defined. The sign of the latent heat is found to be counterintuitive: it is positive when going from the phase where the temperatures and the entropy are higher to the one where these quantities are lower. The effect exists only out of equilibrium and requires conflicting interactions. It is displayed on a lattice gas model of ferromagnetically interacting spin-1/2 particles.Comment: 4 pages, 2 figure

    Minimally Invasive Urological Interventions in Outpatient Clinic on the Example of Prostate Biopsy

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    One of the main directions of improving medical care was the introduction of inpatient forms of medical care for patients who do not require round-the-clock supervision.Aim of the research: to prove the effectiveness and economic feasibility of minimally invasive procedures in outpatient conditions.Materials and methods. The study included 3524 patients in the period from 2010 to 2017, who underwent transrectal prostate biopsy on the basis of the Department of urology of polyclinic No. 195 of the Western district of Moscow. For comparison, the patients were taken, who underwent a biopsy of the prostate gland at the base hospital No. 31, No. 51, No. 17.Results. The average number of biopsies performed in hospital No. 31, No. 51 and No. 17 for the year amounted to 344 biopsies, and the average detectability of prostate cancer was 142 (41.3 %). The average number of biopsies per year in the urology department of the branch number 2 GP No. 195 amounted to 440.5, and the average detectability of prostate cancer – 152.8 (34.7 %). Thus, with comparable inpatient detection of prostate cancer in one large outpatient urology center, an average of 28 % more biopsies are performed (440.5 versus 344) than in 3 hospitals over a comparable period of time.Conclusions. Inpatient technologies can reduce the burden on hospitals. The development of hospital-replacing forms is determined by the need of the population and for efficient use of financial and technical resources of health care
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