On the effect of superfluid flows on the interaction of microwaves with He II

The paper proposes a possible mechanism of interaction of microwaves with superfluid helium that results in an experimentally observed narrow peak of microwave absorption on the frequencies by the order of the roton frequency. The obtained microwave photon absorption coefficient depends on the local equilibrium distribution function which is established due to fast roton-roton and roton-phonon interactions. With the availability of superfluid flows, the local equilibrium distribution function depends on their velocity. The critical velocity of the flows, at which the absorption of microwaves is replaced by their radiation, is found.Comment: 4 page

Microwave Heating of Water, Ice and Saline Solution: Molecular Dynamics Study

In order to study the heating process of water by the microwaves of 2.5-20GHz frequencies, we have performed molecular dynamics simulations by adopting a non-polarized water model that have fixed point charges on rigid-body molecules. All runs are started from the equilibrated states derived from the I$_{c}$ ice with given density and temperature. In the presence of microwaves, the molecules of liquid water exhibit rotational motion whose average phase is delayed from the microwave electric field. Microwave energy is transferred to the kinetic and inter-molecular energies of water, where one third of the absorbed microwave energy is stored as the latter energy. The water in ice phase is scarcely heated by microwaves because of the tight hydrogen-bonded network of water molecules. Addition of small amount of salt to pure water substantially increases the heating rate because of the weakening by defects in the water network due to sloshing large-size negative ions.Comment: 21 pages, 13 figure

Single Cooper pair tunneling induced by non-classical microwaves

A mesoscopic Josephson junction interacting with a mode of non-classical microwaves with frequency $\omega$ is considered. Squeezing of the electromagnetic field drastically affects the dynamics of Cooper tunneling. In particular, Bloch steps can be observed even when the microwaves are in the squeezed vacuum state with {\em zero} average amplitude of the field $\langle E(t) \rangle = 0$. The interval between these steps is double in size in comparison to the conventional Bloch steps.Comment: 8 pages, 2 figures are available upon request to: [email protected]

TE Wave Measurement and Modeling

In the TE wave method, microwaves are coupled into the beam-pipe and the effect of the electron cloud on these microwaves is measured. An electron cloud (EC) density can then be calculated from this measurement. There are two analysis methods currently in use. The first treats the microwaves as being transmitted from one point to another in the accelerator. The second more recent method, treats the beam-pipe as a resonant cavity. This paper will summarize the reasons for adopting the resonant TE wave analysis as well as give examples from CESRTA and DA{\Phi}NE of resonant beam-pipe. The results of bead-pull bench measurements will show some possible standing wave patterns, including a cutoff mode (evanescent) where the field decreases exponentially with distance from the drive point. We will outline other recent developments in the TE wave method including VORPAL simulations of microwave resonances, as well as the simulation of transmission in the presence of both an electron cloud and magnetic fields.Comment: Presented at ECLOUD'12: Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects, La Biodola, Isola d'Elba, Italy, 5-9 June 2012; CERN-2013-002, pp. 193-20

Electromagnetically induced transparency on a single artificial atom

We present experimental observation of electromagnetically induced transparency (EIT) on a single macroscopic artificial "atom" (superconducting quantum system) coupled to open 1D space of a transmission line. Unlike in a optical media with many atoms, the single atom EIT in 1D space is revealed in suppression of reflection of electromagnetic waves, rather than absorption. The observed almost 100 % modulation of the reflection and transmission of propagating microwaves demonstrates full controllability of individual artificial atoms and a possibility to manipulate the atomic states. The system can be used as a switchable mirror of microwaves and opens a good perspective for its applications in photonic quantum information processing and other fields

Resonance-like Goss-Haenchen Shift induced by nano-metal films

The influence of nano-metal films on the Goos-Haenchen shift (GHS) is investigated. The films deposited at the total reflecting surface of a perspex prism/air have a sheet resistance varying between Z = 25 and 3 000 Ohm. A resonance-like enhancement of the shift and of the absorption is found for TE polarized waves, when the sheet resistance approaches the value of the vacuum impedance. For TM waves the influence of the metal films on the GHS is comparatively weak. The experiments are carried out with microwaves. Keywords: Goos-Haenchen shift; nano-metallic films, microwaves PACS: 42.25.Bs, 42.25.Gy, 42.50.-p, 73.40.GkComment: 6 pages, 4 figure

Magnetization switching by microwaves initially rotating in opposite direction to precession

A common understanding of magnetization switching in microwave-assisted magnetization reversal is that the rotation direction of the microwaves should be the same with the precession direction of the magnetization. In this letter however, we show that microwaves initially rotating opposite to the magnetization precession destabilize the magnetization at an equilibrium and induces the switching more efficiently, when the microwave frequency depends on time. This argument is analytically deduced from energy balance equation. We also establish a model satisfying this condition, and confirm magnetization switching solely by microwaves by using numerical simulation.Comment: 5 pages, 4 figure

A classical statistical model for distributions of escape events in swept-bias Josephson junctions

We have developed a model for experiments in which the bias current applied to a Josephson junction is slowly increased from zero until the junction switches from its superconducting zero-voltage state, and the bias value at which this occurs is recorded. Repetition of such measurements yields experimentally determined probability distributions for the bias current at the moment of escape. Our model provides an explanation for available data on the temperature dependence of these escape peaks. When applied microwaves are included we observe an additional peak in the escape distributions and demonstrate that this peak matches experimental observations. The results suggest that experimentally observed switching distributions, with and without applied microwaves, can be understood within classical mechanics and may not exhibit phenomena that demand an exclusively quantum mechanical interpretation.Comment: Eight pages, eight figure