Moscow Institute of Physics and Technology

About: Moscow Institute of Physics and Technology is a education organization based out in Dolgoprudnyy, Russia. It is known for research contribution in the topics: Laser & Plasma. The organization has 8594 authors who have published 16968 publications receiving 246551 citations. The organization is also known as: MIPT & Moscow Institute of Physics and Technology (State University).

Tuneable on-demand single-photon source in the microwave range.

Abstract: An on-demand single-photon source is a key element in a series of prospective quantum technologies and applications. Here we demonstrate the operation of a tuneable on-demand microwave photon source based on a fully controllable superconducting artificial atom strongly coupled to an open-ended transmission line. The atom emits a photon upon excitation by a short microwave π-pulse applied through a control line. The intrinsically limited device efficiency is estimated to be in the range 65–80% in a wide frequency range from 7.75 to 10.5 GHz continuously tuned by an external magnetic field. The actual demonstrated efficiency is also affected by the excited state preparation, which is about 90% in our experiments. The single-photon generation from the single-photon source is additionally confirmed by anti-bunching in the second-order correlation function. The source may have important applications in quantum communication, quantum information processing and sensing. Microwave single photon sources are important for quantum applications, but their design often incorporates a resonator that fixes the frequency of the emitted photon. Here, the authors demonstrate a tuneable on-demand photon source based on an artificial atom asymmetrically coupled to two transmission lines.

Search for t(t)over-barH production in the all-jet final state in proton-proton collisions root s=13 TeV

Abstract: A search is presented for the associated production of a Higgs boson with a top quark pair in the all-jet final state. Events containing seven or more jets are selected from a sample of proton-proton collisions at $$ \sqrt{s}=13 $$ TeV collected with the CMS detector at the LHC in 2016, corresponding to an integrated luminosity of 35.9 fb−1. To separate the $$ \mathrm{t}\overline{\mathrm{t}}\mathrm{H} $$ signal from the irreducible $$ \mathrm{t}\overline{\mathrm{t}}+\mathrm{b}\overline{\mathrm{b}} $$ background, the analysis assigns leading order matrix element signal and background probability densities to each event. A likelihood-ratio statistic based on these probability densities is used to extract the signal. The results are provided in terms of an observed ttH signal strength relative to the standard model production cross section μ = σ/σSM, assuming a Higgs boson mass of 125 GeV. The best fit value is $$ \widehat{\mu}=0.9\pm 0.7\left(\mathrm{stat}\right)\pm 1.3\left(\mathrm{syst}\right)=0.9\pm 1.5\left(\mathrm{tot}\right) $$ , and the observed and expected upper limits are, respectively, μ < 3.8 and < 3.1 at 95% confidence levels.

Probing new physics in B ¯ 0 → D ( * ) τ − ν ¯ τ using the longitudinal, transverse, and normal polarization components of the tau lepton

Abstract: We study the longitudinal, transverse, and normal polarization components of the tau lepton in the decays ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{(*)}{\ensuremath{\tau}}^{\ensuremath{-}}{\overline{\ensuremath{ u}}}_{\ensuremath{\tau}}$ and discuss their role in searching for new physics (NP) beyond the standard model (SM). Starting with a model-independent effective Hamiltonian including non-SM four-Fermi operators, we obtain experimental constraints on different NP scenarios and investigate their effects on the polarization observables. In the SM the longitudinal and transverse polarizations of the tau lepton differ substantially from the corresponding zero lepton mass values of ${P}_{L}=\ensuremath{-}1$ and ${P}_{T}=0$. In addition, ${P}_{L}$ and ${P}_{T}$ are very sensitive to NP effects. For the transverse polarization this holds true, in particular, for the effective tensor operator in the case of ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{*}$ and for the scalar operator in the case of ${\overline{B}}^{0}\ensuremath{\rightarrow}D$. The $T$-odd normal polarization ${P}_{N}$, which is predicted to be negligibly small in the SM, can be very sizable assuming NP complex Wilson coefficients. We also discuss in some detail how the three polarization components of the tau lepton can be measured with the help of its subsequent leptonic and semihadronic decays.

A nanosecond surface dielectric barrier discharge at elevated pressures: time-resolved electric field and efficiency of initiation of combustion

Abstract: We study a nanosecond surface dielectric barrier discharge (SDBD) initiated by negative or positive polarity pulses 10?15?kV in amplitude in a cable, 25?30?ns FWHM, 5?ns rise time, in the regime of a single shot or 3?Hz repetitive frequency. Discharge parameters, namely spatial structure of the discharge and time- and space-resolved electric field are studied in a N2?:?O2?=?4?:?1 mixture for P?=?1?5?atm. The possibility of igniting a combustible mixture with the help of an SDBD is demonstrated using the example of a stoichiometric C2H6?:?O2 mixture at ambient initial temperature and at 1?atm pressure. Flame propagation and ignited volume as a function of time are compared experimentally for two discharge geometries: SDBD and pin-to-pin configurations at the same shape and amplitude of the incident pulse. It is shown that the SDBD can be considered as a multi-point ignition system with maximum energy release near the high-voltage electrode. Numerical modeling of the discharge and subsequent combustion kinetics for the SDBD conditions is performed. The discharge action leads to the production of atoms and radicals as well as to fast gas heating, due to the relaxation of electronic and vibrational degrees of freedom. The calculated ignition delay time is in reasonable agreement with the experimental results.