Microwave source of multigigawatt peak power based on a relativistic backward-wave oscillator and a compressor

The effect of passive compression of frequency-modulated pulses in dispersive media is used to raise the microwave radiation peak power to a multigigawatt level. A waveguide with a helically corrugated surface is applied as a dispersive medium, and a relativistic 3-cm backward-wave oscillator with an accelerating voltage decaying within the pulse duration serves as a source of frequency-modulated pulses. The compression of pulses to an FWHM of 2.2 ns attended by a rise in the peak power by a factor of 4.5 (to 3.2 GW) is demonstrated with a SINUS-6 accelerator.     

Investigation of the diffractive reaction p + N → [∑+ K 0] + N at the proton energy of E p =70 GeV and observation of the decay process X(2000) → ∑+ K 0

The diffractive reaction p + N → [∑⁺ K ⁰] + N induced by 70-GeV protons is investigated at the SPHINX facility. The measured mass spectrum of the ∑⁺ K ⁰ system originating from this reaction shows a resonance structure with a mass of M=1995±18 MeV and a width of Γ=90±32 MeV. The cross section for the formation of this structure is found to be σ=182±38 nb per target nucleon. These data comply well with the results that we obtained previously in studying the reaction p + N → [∑⁰ K ⁺] + N, where we observed the formation of the X(2000) → ∑⁰ K ⁺ state, a candidate for an exotic baryon with hidden strangeness. The measured ratio R of the two branching fractions, R = Br[X(2000) → ∑⁺ K ⁰]/Br[X(2000) → ∑⁰ K ⁺] = 1.91 ± 0.38, is consistent with the value of R=2 expected for an isospin-1/2 baryon.     

Quantum ℛ-Matrices as Universal Qubit Gates

JETP Letters - We study the Chern-Simons approach to the topological quantum computing. We use quantum ℛ-matrices as universal quantum gates and study the approximations of some one-qubit...     

Effective Co-generation of opposite and forward waves in cyclotron-resonance masers

A novel type of the frequency-tunable oscillator based on simultaneous generation of the forward and opposite waves at the same frequency, but at different cyclotron harmonics, is proposed. A spatially periodic helical electron beam allows for strong coupling of the waves. The opposite wave provides the broadband feedback and electron bunching, whereas the forward wave amplifies the arising signal and withdraws the rf power from the interaction region. A 15% efficiency and 5% frequency bandwidth have been achieved in the first experiment.     

Experimental study of CRM with simultaneous excitation of travelingand near-cutoff waves (CARM-gyrotron)

A new variety of RF sources is studied experimentally. In the cyclotron autoresonance maser (CARM)-gyrotron with an open “gyrotron-type” cavity, two regimes of operation are observed: the conventional high-harmonic gyrotron regime, and the CARM-gyrotron regime with effective radiation of the traveling CARM mode. The two-mode character of the electron-wave interaction in the CARM-gyrotron regime was proved experimentally