Ecological consequences of the playgrounds' reconstruction of specialized "park-stadium Khimmash", in Yekaterinburg

In connection with the World Cup in 2018 in the Russian Federation, including the qualifying matches of the World Championship in Yekaterinburg, the Government of the Sverdlovsk Regiondecided to place a training ground on the territory of the "Park-stadium Khimmash". For this purpose, a sports field reconstruction project was created and implemented. The article is devoted to the assessment of negative consequences for plantings of the "Park-stadium Khimmash" in Yekaterinburg as a result of the construction, which led to the destruction of 388 trees, 95 of them are pine trees. The park historically originated on the site of a natural pine plantation. Cutting down so many trees led to further disintegration of the stand. According to the project, the replacement of felled large park trees of pine and birch by willow and apple trees is recommended, which led to the destruction of natural landscapes that have survived in the urban environment. At the same time, not only the aesthetic perception is worsened, but the ecological criteria of the industrial area of the city are also reduced. First of all, the oxygen-producing possibilities of the plantation decreased, which is reflected in the economic assessment of the consequences. © 2019 IOP Publishing Ltd. All rights reserved

Ultra-Slow Light and Enhanced Nonlinear Optical Effects in a Coherently Driven Hot Atomic Gas

We report the observation of small group velocities of order 90 meters per second, and large group delays of greater than 0.26 ms, in an optically dense hot rubidium gas (~360 K). Media of this kind yield strong nonlinear interactions between very weak optical fields, and very sharp spectral features. The result is in agreement with previous studies on nonlinear spectroscopy of dense coherent media

Threshold and linewidth of a mirrorless parametric oscillator

We analyze the above-threshold behavior of a mirrorless parametric oscillator based on resonantly enhanced four wave mixing in a coherently driven dense atomic vapor. It is shown that, in the ideal limit, an arbitrary small flux of pump photons is sufficient to reach the oscillator threshold. We demonstrate that due to the large group-velocity delays associated with coherent media, an extremely narrow oscillator linewidth is possible, making a narrow-band source of non-classical radiation feasible.Comment: revised version to appear in Phys.Rev.Lett., contains discussion on threshold conditions and operation on few-photon leve

Hybrid Architecture for Engineering Magnonic Quantum Networks

We show theoretically that a network of superconducting loops and magnetic particles can be used to implement magnonic crystals with tunable magnonic band structures. In our approach, the loops mediate interactions between the particles and allow magnetic excitations to tunnel over long distances. As a result, different arrangements of loops and particles allow one to engineer the band structure for the magnonic excitations. Furthermore, we show how magnons in such crystals can serve as a quantum bus for long-distance magnetic coupling of spin qubits. The qubits are coupled to the magnets in the network by their local magnetic-dipole interaction and provide an integrated way to measure the state of the magnonic quantum network.Comment: Manuscript: 4 pages, 3 figures. Supplemental Material: 9 pages, 4 figures. V2: Published version in PRA: 14 pages + 8 figures. Substantial rearrangement of the content of the previous versio

Storage of light in atomic vapor

We report an experiment in which a light pulse is decelerated and trapped in a vapor of Rb atoms, stored for a controlled period of time, and then released on demand. We accomplish this storage of light by dynamically reducing the group velocity of the light pulse to zero, so that the coherent excitation of the light is reversibly mapped into a collective Zeeman (spin) coherence of the Rb vapor

Ultraslow light in inhomogeneously broadened media

We calculate the characteristics of ultraslow light in an inhomogeneously broadened medium. We present analytical and numerical results for the group delay as a function of power of the propagating pulse. We apply these results to explain the recently reported saturation behavior [Baldit {\it et al.}, \prl {\bf 95}, 143601 (2005)] of ultraslow light in rare earth ion doped crystal.Comment: 4 pages, 5 figure

Parametric Self-Oscillation via Resonantly Enhanced Multiwave Mixing

We demonstrate an efficient nonlinear process in which Stokes and anti-Stokes components are generated spontaneously in a Raman-like, near resonant media driven by low power counter-propagating fields. Oscillation of this kind does not require optical cavity and can be viewed as a spontaneous formation of atomic coherence grating

Raman Adiabatic Transfer of Optical States

We analyze electromagnetically induced transparency and light storage in an ensemble of atoms with multiple excited levels (multi-Lambda configuration) which are coupled to one of the ground states by quantized signal fields and to the other one via classical control fields. We present a basis transformation of atomic and optical states which reduces the analysis of the system to that of EIT in a regular 3-level configuration. We demonstrate the existence of dark state polaritons and propose a protocol to transfer quantum information from one optical mode to another by an adiabatic control of the control fields

Nonlinear optics via double dark resonances

Double dark resonances originate from a coherent perturbation of a system displaying electromagnetically induced transparency. We experimentally show and theoretically confirm that this leads to the possibility of extremely sharp resonances prevailing even in the presence of considerable Doppler broadening. A gas of 87Rb atoms is subjected to a strong drive laser and a weak probe laser and a radio frequency field, where the magnetic coupling between the Zeeman levels leads to nonlinear generation of a comb of sidebands.Comment: 6 pages, 9 figure