The magnetohydrodynamic squeeze film
International Nuclear Information System (INIS)
Hamza, E.A.
1987-06-01
The motion of an electrically conducting fluid film squeezed between two parallel disks in the presence of a magnetic field applied perpendicular to the disks is studied. Analytic solutions through use of a regular perturbation scheme are obtained. The results show that the electromagnetic forces increase the load carrying capacity considerably. (author). 5 refs, 10 figs, 3 tabs
Hydromagnetic thin film flow: Linear stability
Amaouche, Mustapha
2013-08-30
This paper deals with the long wave instability of an electroconductor fluid film, flowing down an inclined plane at small to moderate Reynolds numbers, under the action of electromagnetic fields. A coherent second order long wave model and two simplified versions of it, referred to as first and second reduced models (FRM and SRM), are proposed to describe the nonlinear behavior of the flow. The modeling procedure consists of a combination of the lubrication theory and the weighted residual approach using an appropriate projection basis. A suitable choice of weighting functions allows a significant reduction of the dimension of the problem. The full model is naturally unique, i.e., independent of the particular form of the trial functions. The linear stability of the problem is investigated, and the influence of electromagnetic field on the flow stability is analyzed. Two cases are considered: the applied magnetic field is either normal or parallel to the fluid flow direction, while the electric field is transversal. The numerical solution of the Orr-Sommerfeld (OS) eigenvalue problem and those of the depth averaging model are used to assess the accuracy of the reduced models. It is found that the current models have the advantage of the Benney-like model, which is known to asymptote the exact solution near criticality. Moreover, far from the instability threshold, the current reduced models continue to follow the OS solution up to moderate Reynolds numbers, while the averaging model diverges rapidly. The model SRM gives better results than FRM beyond sufficiently high Reynolds numbers.
Knox, D. J.
2013-11-14
© 2013 © The authors 2013. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved. The squeeze-film flow of a thin layer of Newtonian fluid filling the gap between a flat impermeable surface moving under a prescribed constant load and a flat thin porous bed coating a stationary flat impermeable surface is considered. Unlike in the classical case of an impermeable bed, in which an infinite time is required for the two surfaces to touch, for a porous bed contact occurs in a finite contact time. Using a lubrication approximation, an implicit expression for the fluid layer thickness and an explicit expression for the contact time are obtained and analysed. In addition, the fluid particle paths are calculated, and the penetration depths of fluid particles into the porous bed are determined. In particular, the behaviour in the asymptotic limit of small permeability, in which the contact time is large but finite, is investigated. Finally, the results are interpreted in the context of lubrication in the human knee joint, and some conclusions are drawn about the contact time of the cartilage-coated femoral condyles and tibial plateau and the penetration of nutrients into the cartilage.
Nonlinear Squeeze Film Dampers without Centralized Springs
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Zhu Changsheng
2000-01-01
Full Text Available In this paper, the bifurcation behavior of a flexible rotor supported on nonlinear squeeze film dampers without centralized springs is analyzed numerically by means of rotor trajectories, Poincar maps, bifurcation diagrams and power spectra, based on the short bearing and cavitated film assumptions. It is shown that there also exist two different operations (i.e., socalled bistable operations in some speed regions in the rotor system supported on the nonlinear squeeze film dampers without centralized springs. In the bistable operation speed regions, the rotor system exhibits synchronous, sub-synchronous, sub-super-synchronous and almost-periodic as well as nonperiodic motions. The periodic bifurcation behaviors of the rotor system supported on nonlinear squeeze film dampers without centralized springs are very complex and require further investigations.
Graphene Squeeze-Film Pressure Sensors.
Dolleman, Robin J; Davidovikj, Dejan; Cartamil-Bueno, Santiago J; van der Zant, Herre S J; Steeneken, Peter G
2016-01-13
The operating principle of squeeze-film pressure sensors is based on the pressure dependence of a membrane's resonance frequency, caused by the compression of the surrounding gas which changes the resonator stiffness. To realize such sensors, not only strong and flexible membranes are required, but also minimization of the membrane's mass is essential to maximize responsivity. Here, we demonstrate the use of a few-layer graphene membrane as a squeeze-film pressure sensor. A clear pressure dependence of the membrane's resonant frequency is observed, with a frequency shift of 4 MHz between 8 and 1000 mbar. The sensor shows a reproducible response and no hysteresis. The measured responsivity of the device is 9000 Hz/mbar, which is a factor 45 higher than state-of-the-art MEMS-based squeeze-film pressure sensors while using a 25 times smaller membrane area.
Squeezing-out dynamics in free-standing smectic films
Energy Technology Data Exchange (ETDEWEB)
S̀liwa, Izabela, E-mail: izasliwa@ifmpan.poznan.pl [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznaǹ (Poland); Vakulenko, A.A. [Saint Petersburg Institute for Machine Sciences, The Russian Academy of Sciences, Saint Petersburg 199178 (Russian Federation); Zakharov, A.V., E-mail: alexandre.zakharov@yahoo.ca [Saint Petersburg Institute for Machine Sciences, The Russian Academy of Sciences, Saint Petersburg 199178 (Russian Federation)
2016-05-06
Highlights: • We model the dynamics of layer transitions. • We model the thermally activated nucleation of a small hole. • We model the dynamics of squeezing-out one layer. - Abstract: We have carried out a theoretical study of the dynamics of the squeezing-out of one layer from the N-layer free-standing smectic film (FSSF) coupled with a meniscus, during the layer-thinning process. Squeezing-out is initiated by a thermally activated nucleation process in which a density fluctuation forms a small void in the center of the circular FSSF. The pressure gradient develops between the squeezed-out and nonsqueezed-out areas and is responsible for the driving out of one or several layer(s) from the N-layer smectic film. The dynamics of the boundary between these areas in the FSSF is studied by the use of the conservation laws for mass and linear momentum with accounting for the coupling between the meniscus and the smectic film. This coupling has a strong effect on the dynamics of the squeezing-out process and may significantly change the time which is needed to completely squeezed-out one or several layer(s) from the N-layer smectic film.
A Study Of Magnetic Fluid Based Squeeze Film Between Porous ...
African Journals Online (AJOL)
Efforts have been made to study and analyze the effect of surface roughness on the performance of magnetic fluid based squeeze film between porous elliptic plates. The transverse roughness of the bearing surface is characterized by a stochastic random variable with non-zero mean, variance and skewness.
An Experimental Study on Steel and Teflon Squeeze Film Dampers
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Asad A. Khalid
2006-01-01
Full Text Available In this paper, the vibration analysis on Teflon and steel squeeze film dampers has been carried out. At different frequency ranges, vibration amplitude and the resonance frequency are measured. The eccentricity ratio at resonance speed has been determined. Results show that the vibration amplitude of the steel damper is 10% less at resonance compared with the Teflon damper. On the other hand, saving weight of 36% has been achieved by using the Teflon damper.
Analysis of an Electrostatic MEMS Squeeze-film Drop Ejector
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Edward P. Furlani
2009-10-01
Full Text Available We present an analysis of an electrostatic drop-on-demand MEMS fluid ejector. The ejector consists of a microfluidic chamber with a piston that is suspended a few microns beneath a nozzle plate. A drop is ejected when a voltage is applied between the orifice plate and the piston. This produces an electrostatic force that moves the piston towards the nozzle. The moving piston generates a squeeze-film pressure distribution that causes drop ejection. We discuss the operating physics of the ejector and present a lumped-element model for predicting its performance. We calibrate the model using coupled structural-fluidic CFD analysis.
Investigation of Squeeze Film Damping and Associated Loads
DEFF Research Database (Denmark)
Johansen, Per; Bender, Niels Christian; Hansen, Anders Hedegaard
2017-01-01
-viscous case. In consequence, this enable insights concerning the influence of piezo-viscosity on this damping effect. These models are used to investigate the loads, which the approaching surfaces experiences. Based on Hertzian theory, comparisons of impact loads and the dynamic squeeze loading are performed......Digital hydraulics have attracted attention towards fast switching valves and the increased focus on reliable fluid power entail that the lifetime of such valves is of great concern. An inherent feature of most valves for digital hydraulics is that of a mechanical end stop. Consequently...... is reviewed with a focus on maximum surface stresses. Using the Barus relation for viscosity-pressure dependency and different film geometries, the classical lubrication theory is applied together with the equation of motion, to obtain the gap height motion equation, both for the iso-viscous and piezo...
Leung, Roger; Cheung, Howard; Gang, Hong; Ye, Wenjing
2010-01-01
Squeeze-film damping on microresonators is a significant damping source even when the surrounding gas is highly rarefied. This article presents a general modeling approach based on Monte Carlo (MC) simulations for the prediction of squeeze
The spectral analysis of an aero-engine assembly incorporating a squeeze-film damper
Holmes, R.; Dede, M. M.
1989-01-01
Aero-engine structures have very low inherent damping and so artificial damping is often introduced by pumping oil into annular gaps between the casings and the outer races of some or all of the rolling-element bearings supporting the rotors. The thin oil films so formed are called squeeze film dampers and they can be beneficial in reducing rotor vibration due to unbalance and keeping to reasonable limits the forces transmitted to the engine casing. However, squeeze-film dampers are notoriously non-linear and as a result can introduce into the assembly such phenomena as subharmonic oscillations, jumps and combination frequencies. The purpose of the research is to investigate such phenomena both theoretically and experimentally on a test facility reproducing the essential features of a medium-size aero engine. The forerunner of this work was published. It was concerned with the examination of a squeeze-film damper in series with housing flexibility when supporting a rotor. The structure represented to a limited extent the essentials of the projected Rolls Royce RB401 engine. That research demonstrated the ability to calculate the oil-film forces arising from the squeeze film from known motions of the bearing components and showed that the dynamics of a shaft fitted with a squeeze film bearing can be predicted reasonably accurately. An aero-engine will normally have at least two shafts and so in addition to the excitation forces which are synchronous with the rotation of one shaft, there will also be forces at other frequencies from other shafts operating on the squeeze-film damper. Theoretical and experimental work to consider severe loading of squeeze-film dampers and to include these additional effects are examined.
Dynamic characteristics of Non Newtonian fluid Squeeze film damper
Palaksha, C. P.; Shivaprakash, S.; Jagadish, H. P.
2016-09-01
The fluids which do not follow linear relationship between rate of strain and shear stress are termed as non-Newtonian fluid. The non-Newtonian fluids are usually categorized as those in which shear stress depends on the rates of shear only, fluids for which relation between shear stress and rate of shear depends on time and the visco inelastic fluids which possess both elastic and viscous properties. It is quite difficult to provide a single constitutive relation that can be used to define a non-Newtonian fluid due to a great diversity found in its physical structure. Non-Newtonian fluids can present a complex rheological behaviour involving shear-thinning, viscoelastic or thixotropic effects. The rheological characterization of complex fluids is an important issue in many areas. The paper analyses the damping and stiffness characteristics of non-Newtonian fluids (waxy crude oil) used in squeeze film dampers using the available literature for viscosity characterization. Damping and stiffness characteristic will be evaluated as a function of shear strain rate, temperature and percentage wax concentration etc.
Effects of Velocity-Slip and Viscosity Variation in Squeeze Film Lubrication of Two Circular Plates
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R.R. Rao
2013-03-01
Full Text Available A generalized form of Reynolds equation for two symmetrical surfaces is taken by considering velocity-slip at the bearing surfaces. This equation is applied to study the effects of velocity-slip and viscosity variation for the lubrication of squeeze films between two circular plates. Expressions for the load capacity and squeezing time obtained are also studied theoretically for various parameters. The load capacity and squeezing time decreases due to slip. They increase due to the presence of high viscous layer near the surface and decrease due to low viscous layer.
Squeeze-film damping characteristics of cantilever microresonators ...
African Journals Online (AJOL)
user
perturbation approach does not apply to cantilever plates because of ...... Direct coupling of electrostatic and structural domain has been achieved using ... forces are computed to obtain the modal squeeze stiffness and damping parameters.
A Brief Discussion Regarding Types of Cavitation in Squeeze Film Dampers and Cavitation Effects
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Laurentiu MORARU
2017-03-01
Full Text Available Squeeze film dampers (SFD are probably the most used shaft control devices in aircraft jet engines; SFDs consist in oil films, elastic elements and various antirotational devices that tune the stiffness and damping of the shafts’ supports and consequently adjust the lateral dynamics of the shaft. Fluid layers in SFDs are usually thin, hence the modeling can often be done using the Reynolds’ theory,; however, some of the main features of the film, namely the behavior of the fluid in the divergent, negative squeeze area, where discontinuities may appear in the liquid, are still subject to intense research. This paper will discuss some aspects regarding the types of cavitation that appear in squeeze film dampers and some of the effects of cavitation on the SFDs.
Effect of oscillation mode on the free-molecule squeeze-film air damping
Gang Hong,
2010-01-01
A 3D Monte Carlo (MC) simulation approach is developed and employed to study the effect of the oscillation mode on the squeeze-film air damping in the free-molecule regime. By tracking individual gas molecule\\'s motion and its interaction with the resonator, the MC approach is by far the most accurate modeling approach for the modeling of squeeze-film damping in the free-molecule regime. The accuracy of this approach is demonstrated on several cases in which either analytical solutions or experimental measurements are available. It has been found that unlike the case when resonators oscillate in an unbounded domain, squeeze film damping is very sensitive to the mode shape, which implies that some of the existing modeling approaches based on rigid-resonator assumption may not be accurate when applied to model resonators oscillating at their deformed shape. ©2010 IEEE.
Zorzi, E. S.; Burgess, G.; Cunningham, R.
1980-01-01
This paper describes the design and testing of an elastomer damper on a super-critical power transmission shaft. The elastomers were designed to provide acceptable operation through the fourth bending mode and to control synchronous as well as nonsynchronous vibration throughout the operating range. The design of the elastomer was such that it could be incorporated into the system as a replacement for a squeeze-film damper without a reassembly, which could have altered the imbalance of the shaft. This provided a direct comparison of the elastomer and squeeze-film dampers without having to assess the effect of shaft imbalance changes.
Study of Nonlinear MHD Tribological Squeeze Film at Generalized Magnetic Reynolds Numbers Using DTM.
Rashidi, Mohammad Mehdi; Freidoonimehr, Navid; Momoniat, Ebrahim; Rostami, Behnam
2015-01-01
In the current article, a combination of the differential transform method (DTM) and Padé approximation method are implemented to solve a system of nonlinear differential equations modelling the flow of a Newtonian magnetic lubricant squeeze film with magnetic induction effects incorporated. Solutions for the transformed radial and tangential momentum as well as solutions for the radial and tangential induced magnetic field conservation equations are determined. The DTM-Padé combined method is observed to demonstrate excellent convergence, stability and versatility in simulating the magnetic squeeze film problem. The effects of involved parameters, i.e. squeeze Reynolds number (N1), dimensionless axial magnetic force strength parameter (N2), dimensionless tangential magnetic force strength parameter (N3), and magnetic Reynolds number (Rem) are illustrated graphically and discussed in detail. Applications of the study include automotive magneto-rheological shock absorbers, novel aircraft landing gear systems and biological prosthetics.
Study of Nonlinear MHD Tribological Squeeze Film at Generalized Magnetic Reynolds Numbers Using DTM.
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Mohammad Mehdi Rashidi
Full Text Available In the current article, a combination of the differential transform method (DTM and Padé approximation method are implemented to solve a system of nonlinear differential equations modelling the flow of a Newtonian magnetic lubricant squeeze film with magnetic induction effects incorporated. Solutions for the transformed radial and tangential momentum as well as solutions for the radial and tangential induced magnetic field conservation equations are determined. The DTM-Padé combined method is observed to demonstrate excellent convergence, stability and versatility in simulating the magnetic squeeze film problem. The effects of involved parameters, i.e. squeeze Reynolds number (N1, dimensionless axial magnetic force strength parameter (N2, dimensionless tangential magnetic force strength parameter (N3, and magnetic Reynolds number (Rem are illustrated graphically and discussed in detail. Applications of the study include automotive magneto-rheological shock absorbers, novel aircraft landing gear systems and biological prosthetics.
Vasanth, K. R.; Hanumagowda, B. N.; Santhosh Kumar, J.
2018-04-01
Squeeze film investigations focus upon film pressure, load bearing quantity and the minimum thickness of film. The combined effect of pressure viscous dependent and non- Newtonian couple stress in porous annular plate is studied. The modified equations of one dimensional pressure, load bearing quantity, non dimensional squeeze time are obtained. The conclusions obtained in the study are found to be in very good agreement compared to the previous results which are published. The load carrying capacity is increased due to the variation in the pressure dependent viscosity and also due to the couple stress effect. Finally this results in change in the squeeze film timings.
Using squeeze-film effect to reduce surface friction in electrostatic actuators
DEFF Research Database (Denmark)
Zsurzsan, Tiberiu-Gabriel; Yamamoto, Akio; Zhang, Zhe
2015-01-01
This paper presents a method of reducing load friction in two degrees-of-freedom (2-DOF) transparent electrostatic induction actuator by using vibration-induced squeeze film effect. An experimental set-up was built to prove the concept. An overall 70% reduction in required driving voltage...
A macromodel for squeeze-film air damping in the free-molecule regime
Hong, Gang; Ye, Wenjing
2010-01-01
A three-dimensional Monte Carlo(MC) simulation approach is developed for the accurate prediction of the squeeze-film air damping on microresonators in the free-molecule gas regime. Based on the MC simulations and the analytical traveling
Modelling of magnetorheological squeeze film dampers for vibration suppression of rigid rotors
Czech Academy of Sciences Publication Activity Database
Zapoměl, Jaroslav; Ferfecki, Petr; Kozánek, Jan
2017-01-01
Roč. 127, Jul SI (2017), s. 191-197 ISSN 0020-7403 R&D Projects: GA ČR GA15-06621S Institutional support: RVO:61388998 Keywords : squeeze film damper * magnetorheological fluid * bilinear material * rigid rotor * frequency response Subject RIV: JR - Other Machinery OBOR OECD: Mechanical engineering Impact factor: 2.884, year: 2016
DEFF Research Database (Denmark)
Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.
2010-01-01
3H8, C4H10, C8H18, C9H20, C10H22, C14H30 and C16H34, confined between corrugated gold surfaces. Well defined molecular layers develop in the lubricant film when the width is of the order of a few atomic diameters. An external squeezing pressure induces discontinuous, thermally activated changes...
Effect of oscillation mode on the free-molecule squeeze-film air damping
Gang Hong,; Wenjing Ye,
2010-01-01
A 3D Monte Carlo (MC) simulation approach is developed and employed to study the effect of the oscillation mode on the squeeze-film air damping in the free-molecule regime. By tracking individual gas molecule's motion and its interaction
Directory of Open Access Journals (Sweden)
M. Rajashekar
2012-01-01
Full Text Available The combined effects of couple stress and surface roughness on the MHD squeeze-film lubrication between a sphere and a porous plane surface are analyzed, based upon the thin-film magnetohydrodynamic (MHD theory. Using Stoke’s theory to account for the couple stresses due to the microstructure additives and the Christensen’s stochastic method developed for hydrodynamic lubrication of rough surfaces derives the stochastic MHD Reynolds-type equation. The expressions for the mean MHD squeeze-film pressure, mean load-carrying capacity, and mean squeeze-film time are obtained. The results indicate that the couple stress fluid in the film region enhances the mean MHD squeeze-film pressure, load-carrying capacity, and squeeze-film time. The effect of roughness parameter is to increase (decrease the load-carrying capacity and lengthen the response time for azimuthal (radial roughness patterns as compared to the smooth case. Also, the effect of porous parameter is to decrease the load-carrying capacity and increase the squeeze-film time as compared to the solid case.
Leung, Roger
2010-03-31
Squeeze-film damping on microresonators is a significant damping source even when the surrounding gas is highly rarefied. This article presents a general modeling approach based on Monte Carlo (MC) simulations for the prediction of squeeze-film damping on resonators in the freemolecule regime. The generality of the approach is demonstrated in its capability of simulating resonators of any shape and with any accommodation coefficient. The approach is validated using both the analytical results of the free-space damping and the experimental data of the squeeze-film damping on a clamped-clamped plate resonator oscillating at its first flexure mode. The effect of oscillation modes on the quality factor of the resonator has also been studied and semi-analytical approximate models for the squeeze-film damping with diffuse collisions have been developed.
Improving the Validity of Squeeze Film Air-Damping Model of MEMS Devices with Border Effect
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Cheng Bai
2014-01-01
Full Text Available Evaluation of squeezed film air damping is critical in the design and control of dynamic MEMS devices. The published squeezed film air damping models are generally derived from the analytical solutions of Reynolds equation or its other modified forms under the supposition of trivial pressure boundary conditions on the peripheral borders. These treatments ignoring the border effect can not give faithful result for structure with smaller air venting gap or the double-gimbaled structure in which the inner frame and outer one affect the air venting. In this paper, we use Green’s function to solve the nonlinear Reynolds equation with inhomogeneous boundary conditions. For two typical normal motion cases of parallel plate, the analytical models of squeeze film damping force with border effect are established. The viscous and inertial losses with real values and image values acoustic impedance are all included in the model. These models reduced the time consumption while giving satisfactory result. Without multifield coupling analysis, the estimation of the dynamic behavior of MEMS device is also allowed, and the simulation of the system performance is more convenient.
Squeeze-Film Air Damping of a Five-Axis Electrostatic Bearing for Rotary Micromotors.
Wang, Shunyue; Han, Fengtian; Sun, Boqian; Li, Haixia
2017-05-13
Air-film damping, which dominates over other losses, plays a significant role in the dynamic response of many micro-fabricated devices with a movable mass suspended by various bearing mechanisms. Modeling the damping characteristics accurately will be greatly helpful to the bearing design, control, and test in various micromotor devices. This paper presents the simulated and experimental squeeze-film air damping results of an electrostatic bearing for use in a rotary high-speed micromotor. It is shown that the boundary condition to solve the three-dimensional Reynolds equation, which governs the squeeze-film damping in the air gap between the rotor and its surrounding stator sealed in a three-layer evacuated cavity, behaves with strong cross-axis coupling characteristics. To accurately characterize the damping effect, a set of multiphysics finite-element simulations are performed by computing both the rotor velocity and the distribution of the viscous damping force acting on the rotor. The damping characteristics varying with several key structure parameters are simulated and discussed to optimize the device structure for desirable rotor dynamics. An electrical measurement method is also proposed and applied to validate the numerical results of the damping coefficients experimentally. Given that the frequency response of the electric bearing is critically dependent on the damping coefficients at atmospheric pressure, a solution to the air-film damping measurement problem is presented by taking approximate curve fitting of multi-axis experimental frequency responses. The measured squeeze-film damping coefficients for the five-axis electric bearing agrees well with the numerical solutions. This indicates that numerical multiphysics simulation is an effective method to accurately examine the air-film damping effect for complex device geometry and arbitrary boundary condition. The accurate damping coefficients obtained by FEM simulation will greatly simplify the design
On the validity of the classical hydrodynamic lubrication theory applied to squeeze film dampers
International Nuclear Information System (INIS)
Danaila, S; Moraru, L
2010-01-01
Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. The SFD - squirrel cage combination is probably the most used system for tuning the stiffness and damping of the supports for rotors installed on ball bearings. Squeeze film dampers are essentially hydrodynamic bearings which contain the ball bearings housings of ball-bearings supported shafts. Consequently, the oil film within the SFD are influenced only by the precession and nutation of the shaft, that is the flow of the oil within the damper is not directly influenced by the spin of the rotor. However, in the classical theory, the flow in the thin film is also governed by the Reynolds equation. In this paper, some of the limits of the classical theory of the SFD are discussed and theoretical and experimental studies, which illustrate the ideas presented herein, are presented as well. The orbits of an unbalanced rotor that is supported by a ball-bearings-SFD-squirrel-cage assembly at one end and by rigidly mounted ball bearings at the other end are computed using the bearing forces provided by the classical short bearing theory. The numerical model also includes the properties of the squirrel cage. The parameters of the squirrel cage were measured, together with the effect of the friction within the assembly. Experimental unbalance responses were also collected for various rotation speeds and unbalances to validate the numerical simulations.
Controlling rotordynamic response without squeeze-film dampers (SFDs)
International Nuclear Information System (INIS)
Jiffri, S; Garvey, S
2009-01-01
SFDs are widely used in rotating machinery to provide damping in order to control rotordynamic response. Although popular, under certain conditions SFDs pose problems such as causing non-synchronous vibration arising from unbalance forces interacting with fluid-film forces affected by cavitation. Furthermore, in the interests of moving towards oil-free rotating machines, the need arises to find alternative means of rotordynamic response control. In choosing a new vibration control technology, it is first necessary to consider certain general, configuration-independent criteria. For example, does the actuation method provide a limited stroke (eg. piezoelectric or giant magnetostrictive) or is the stroke a ''motorised'' solution (eg. an ultrasonic motor directly driving the actuator or a pump acting to vary the fill level of closed deformable volumes with incompressible fluid) Is the work per stroke per unit mass of the actuator material sufficient to provide the maximum stroke and force required for the control? What is the bandwidth of the actuator? In the case of electromechanical actuation, what is the coupling factor? Can the elements of the actuator withstand the high temperatures of the operating environment? Is the solution an active or passive one? What are the fatigue properties of the materials used in the actuator? These are some of the questions that need to be considered when evaluating a new control method. Once the significant properties have been identified, it is necessary to consider each of these in the context of the intended application. If one considers the actuation type, in the limited stroke case it will be required for the actuation to take place at synchronous frequency and the work per stroke per unit mass will determine the quantity of material required. For some applications - particularly aero-engines - one seeks to minimise overall mass and therefore materials with high values of work per stroke per unit mass are attractive. By
Some stable hydromagnetic equilibria
Energy Technology Data Exchange (ETDEWEB)
Johnson, J L; Oberman, C R; Kulsrud, R M; Frieman, E A [Project Matterhorn, Princeton University, Princeton, NJ (United States)
1958-07-01
We have been able to find and investigate the properties of equilibria which are hydromagnetically stable. These equilibria can be obtained, for example, by wrapping conductors helically around the stellarator tube. Systems with I = 3 or 4 are indicated to be optimum for stability purposes. In some cases an admixture of I = 2 fields can be advantageous for achieving equilibrium. (author)
Nonlinear Dynamics and Chaos of Microcantilever-Based TM-AFMs with Squeeze Film Damping Effects
Directory of Open Access Journals (Sweden)
Jie-Yu Chen
2009-05-01
Full Text Available In Atomic force microscope (AFM examination of a vibrating microcantilever, the nonlinear tip-sample interaction would greatly influence the dynamics of the cantilever. In this paper, the nonlinear dynamics and chaos of a tip-sample dynamic system being run in the tapping mode (TM were investigated by considering the effects of hydrodynamic loading and squeeze film damping. The microcantilever was modeled as a spring-mass-damping system and the interaction between the tip and the sample was described by the Lennard-Jones (LJ potential. The fundamental frequency and quality factor were calculated from the transient oscillations of the microcantilever vibrating in air. Numerical simulations were carried out to study the coupled nonlinear dynamic system using the bifurcation diagram, Poincaré maps, largest Lyapunov exponent, phase portraits and time histories. Results indicated the occurrence of periodic and chaotic motions and provided a comprehensive understanding of the hydrodynamic loading of microcantilevers. It was demonstrated that the coupled dynamic system will experience complex nonlinear oscillation as the system parameters change and the effect of squeeze film damping is not negligible on the micro-scale.
A Squeeze-film Damping Model for the Circular Torsion Micro-resonators
Yang, Fan; Li, Pu
2017-07-01
In recent years, MEMS devices are widely used in many industries. The prediction of squeeze-film damping is very important for the research of high quality factor resonators. In the past, there have been many analytical models predicting the squeeze-film damping of the torsion micro-resonators. However, for the circular torsion micro-plate, the works over it is very rare. The only model presented by Xia et al[7] using the method of eigenfunction expansions. In this paper, The Bessel series solution is used to solve the Reynolds equation under the assumption of the incompressible gas of the gap, the pressure distribution of the gas between two micro-plates is obtained. Then the analytical expression for the damping constant of the device is derived. The result of the present model matches very well with the finite element method (FEM) solutions and the result of Xia’s model, so the present models’ accuracy is able to be validated.
Hanumagowda, B. N.; Salma, A.; Nagarajappa, C. S.
2018-04-01
The theoretical discussion is carried out for understanding the combined study of MHD, rough surface and couple-stress in the presence of applied magnetic field between two curved circular plates is present analysis. Modified Reynolds Equations accounting for rough surface using stochastic model of Christensen are mathematically formulated. The close form derivations for pressure, load-supporting capacity and response-film time are obtained. Our results shows that, there is an significant increase (decrease) for pressure, load-supporting capacity and squeeze film time due to the effect of azimuthal (radial) roughness parameter when compared to the Hanumagowda.et.al [14] and numerical data of load supporting capacity and response time are given in Table for engineering applications.
Czech Academy of Sciences Publication Activity Database
Ferfecki, P.; Zapoměl, Jaroslav; Kozánek, Jan
2017-01-01
Roč. 104, February (2017), s. 1-11 ISSN 0965-9978 R&D Projects: GA ČR GA15-06621S Institutional support: RVO:61388998 Keywords : magnetorheological squeeze film dampers * magnetorheological oils * closed form formulas * multiphysical problem Subject RIV: JR - Other Machinery OBOR OECD: Mechanical engineering Impact factor: 3.000, year: 2016
Bifurcations in the response of a flexible rotor in squeeze-film dampers with retainer springs
International Nuclear Information System (INIS)
Inayat-Hussain, Jawaid I.
2009-01-01
Squeeze-film dampers are commonly used in conjunction with rolling-element or hydrodynamic bearings in rotating machinery. Although these dampers serve to provide additional damping to the rotor-bearing system, there have however been some cases of rotors mounted in these dampers exhibiting non-linear behaviour. In this paper a numerical study is undertaken to determine the effects of design parameters, i.e., gravity parameter, W, mass ratio, α, and stiffness ratio, K, on the bifurcations in the response of a flexible rotor mounted in squeeze-film dampers with retainer springs. The numerical simulations were undertaken for a range of speed parameter, Ω, between 0.1 and 5.0. Numerical results showed that increasing K causes the onset speed of bifurcation to increase, whilst an increase of α reduces the onset speed of bifurcation. For a specific combination of K and α values, the onset speed of bifurcation appeared to be independent of W. The instability of the rotor response at this onset speed was due to a saddle-node bifurcation for all the parameter values investigated in this work with the exception of the combination of α = 0.1 and K = 0.5, where a secondary Hopf bifurcation was observed. The speed range of non-synchronous response was seen to decrease with the increase of α; in fact non-synchronous rotor response was totally absent for α=0.4. With the exception of the case α = 0.1, the speed range of non-synchronous response was also seen to decrease with the increase of K. Multiple responses of the rotor were observed at certain values of Ω for various combinations of parameters W, α and K, where, depending on the values of the initial conditions the rotor response could be either synchronous or quasi-periodic. The numerical results presented in this work were obtained for an unbalance parameter, U, value of 0.1, which is considered as the upper end of the normal unbalance range of most practical rotor systems. These results provide some insights
Force effects on rotor of squeeze film damper using Newtonian and non-Newtonian fluid
Dominik, Šedivý; Petr, Ferfecki; Simona, Fialová
2017-09-01
This article presents the evaluation of force effects on rotor of squeeze film damper. Rotor is eccentric placed and its motion is translate-circular. The amplitude of rotor motion is smaller than its initial eccentricity. The force effects are calculated from pressure and viscous forces which were gained by using computational modeling. Two types of fluid were considered as filling of damper. First type of fluid is Newtonian (has constant viscosity) and second type is magnetorheological fluid (does not have constant viscosity). Viscosity of non-Newtonian fluid is given using Bingham rheology model. Yield stress is a function of magnetic induction which is described by many variables. The most important variables of magnetic induction are electric current and gap width which is between rotor and stator. Comparison of application two given types of fluids is shown in results.
A macromodel for squeeze-film air damping in the free-molecule regime
Hong, Gang
2010-01-07
A three-dimensional Monte Carlo(MC) simulation approach is developed for the accurate prediction of the squeeze-film air damping on microresonators in the free-molecule gas regime. Based on the MC simulations and the analytical traveling-time distribution, a macromodel, which relates air damping directly with device dimensions and operation parameters, is constructed. This model provides an efficient tool for the design of high-performance microresonators. The accuracy of the macromodel is validated through the modeling of the quality factors of several microresonators. It has been found that the relative errors of the quality factors of two resonators, as compared with experimental data, are 3.9% and 5.7%, respectively. The agreements between the macromodel results and MC simulation results, on the other hand, are excellent in all cases considered.
International Nuclear Information System (INIS)
Shah, R.C.; Bhat, M.V.
2004-01-01
Ferrofluid squeeze film in an axially undefined porous journal bearing was analyzed to determine its performance considering anisotropic permeability of the porous facing and slip velocity at the interface of porous matrix and film region using Jenkins flow model. Expressions were obtained for dimensionless pressure, load capacity and response time of the squeeze film. How to deduce results for no-slip case, isotropic porous case and for Neuringer-Rosensweig model case were indicated. The computed values of dimensionless load capacity and response time were displayed in graphical form. They increased with increasing values of eccentricity ratio and anisotropic parameter while they decreased with increasing values of slip parameter or material parameter of Jenkins model
ZHU, C. S.; ROBB, D. A.; EWINS, D. J.
2002-05-01
The multiple-solution response of rotors supported on squeeze film dampers is a typical non-linear phenomenon. The behaviour of the multiple-solution response in a flexible rotor supported on two identical squeeze film dampers with centralizing springs is studied by three methods: synchronous circular centred-orbit motion solution, numerical integration method and slow acceleration method using the assumption of a short bearing and cavitated oil film; the differences of computational results obtained by the three different methods are compared in this paper. It is shown that there are three basic forms for the multiple-solution response in the flexible rotor system supported on the squeeze film dampers, which are the resonant, isolated bifurcation and swallowtail bifurcation multiple solutions. In the multiple-solution speed regions, the rotor motion may be subsynchronous, super-subsynchronous, almost-periodic and even chaotic, besides synchronous circular centred, even if the gravity effect is not considered. The assumption of synchronous circular centred-orbit motion for the journal and rotor around the static deflection line can be used only in some special cases; the steady state numerical integration method is very useful, but time consuming. Using the slow acceleration method, not only can the multiple-solution speed regions be detected, but also the non-synchronous response regions.
Dynamic Analysis of a Rotor System Supported on Squeeze Film Damper with Air Entrainment
Zhang, Wei; Han, Bingbing; Zhang, Kunpeng; Ding, Qian
2017-12-01
Squeeze film dampers (SFDs) are widely used in compressors and turbines to suppress the vibration while traversing critical speeds. In practical applications, air ingestion from the outside environment and cavitation may lead to a foamy lubricant that weakens oil film damping and dynamic performance of rotor system. In this paper, a rigid rotor model is established considering both lateral and pitching vibration under different imbalance excitations to evaluate the effect of air entrainment on rotor system. Tests with three different imbalances are carried out on a rotor-SFD apparatus. Volume controlled air in mixture ranging from pure oil to all air are supplied to the SFD. The transient response of rotor is measured in the experiments. The results show that two-phase flow produces significant influence on the system stability and dynamical response. The damping properties are weakened by entrained air, such as the damping on high frequency components of rolling ball bearing. Super-harmonic resonance and bifurcation are observed, as well as the low frequency components due to air entrainment.
Czech Academy of Sciences Publication Activity Database
Hlaváček, Miroslav
2005-01-01
Roč. 127, č. 1 (2005), s. 141-147 ISSN 0742-4787 R&D Projects: GA ČR(CZ) GA103/04/0150 Institutional research plan: CEZ:AV0Z20710524 Keywords : cyclic loading * human ankle joint * squeeze-film lubrication * synovial fluid filtration * synovial gel formation Subject RIV: JJ - Other Materials Impact factor: 0.682, year: 2005
Directory of Open Access Journals (Sweden)
Waleed F. Faris
2008-01-01
Full Text Available This work is devoted to the fabrication and investigation of the Squeeze Film Dampers (SFDs which are widely used in many applications. This include the fabrication of a test rig and several dampers with different sizes and two different materials which composite and non-composite. Composite dampers (Glass/epoxy, each consists of 30 layers, were fabricated by hand lay-up method. Outer and inner diameters of all the fabricated dampers were maintained as 60 and 40 mm respectively. Non-composite dampers (Steel were fabricated and tested using turning machine. Three dampers of different lengths were examined for both materials. A rotor-bearing system for the analysis has been designed and fabricated. The test rig consists of mild steel shaft, two supports, oil pressure system, and two self-alignment ball bearings were fixed on each end support. Two squeeze film dampers were used for the two support ends. Vibration amplitude has been examined for all the fabricated dampers at different shaft rotational speeds. The first resonance speed was examined for all the dampers tested. Results show that the vibration amplitude of the steel damper was lower than Glass/epoxy dampers with the same L/D ratio. On the other hand, a considerable weight saving has been achieved by using Glass/epoxy composite dampers. It has been found that the performance of squeeze film damper improved with increasing length/diameter ratio (L/D within the range tested.
Design and modeling of semi-active squeeze film dampers using magneto-rheological fluids
International Nuclear Information System (INIS)
Kim, Keun-Joo; Lee, Chong-Won; Koo, Jeong-Hoi
2008-01-01
Conventional squeeze film dampers (SFDs) have shown their effectiveness in suppressing unbalanced vibrations in rotor systems, particularly supported by rolling element bearings. Recently, there is an increasing demand for 'controllable' SFDs to meet the need of modern rotating machinery, characterized by high operating speed and high load capacity. Thus, this paper presents a controllable semi-active SFD using magneto-rheological (MR) fluids, focusing on its design and modeling. It offers a comprehensive design method and an innovative experimental identification and modeling technique for MR-SFDs. The primary goal of the MR-SFD design is set to maximize its dynamic control bandwidth, and the design method includes the material selection, magnetic circuit analysis and sealing element design. After constructing a prototype MR-SFD based on the final design, this work investigated how some of the critical design parameters affect the performance of the MR-SFD (i.e. its dynamic control bandwidth change). Furthermore, it characterized the damper's dynamic behavior experimentally using a novel excitation method that adopts active magnetic bearing (AMB) units. Unlike conventional methods, the AMB system was able to precisely control the amplitude and frequency of the input excitation, enabling us to obtain the nonlinear dynamic stiffness properties of the MR-SFD with varying input current. In modeling the dynamic behavior of the MR-SFD, this study employed the describing function method. The describing function analysis effectively captured the nonlinear dynamic behavior of the MR-SFD
Influence of squeeze film damping on the higher-order modes of clamped–clamped microbeams
Alcheikh, Nouha
2016-05-06
This paper presents an experimental study and a finite-element analysis of the effect of squeeze film damping on the resonance frequency and quality factor of the higher-order flexure vibrations modes of clamped-clamped microbeams. Viscoelastic and silicon nitride microbeams are fabricated and are electrostatically actuated by various electrode configurations to trigger the first, second, and third modes. The damping characteristic and the resonance frequency of these modes are examined for a wide range of gas pressure and electrostatic voltage loads. The results of the silicon nitride beams and viscoelastic beams are compared. It is found that the intrinsic material loss is the major dissipation mechanism at low pressure for the viscoelastic microbeams, significantly limiting their quality factor. It is also found that while the silicon nitride beams show higher quality factors at the intrinsic and molecular regimes of pressure, due to their low intrinsic loss, their quality factors near atmospheric pressure are lower than those of the viscoelastic microbeams. Further, the higher-order modes of all the beams show much higher quality factors at atmospheric pressure compared to the first mode, which could be promising for operating such resonators in air. Experimental results and finite element model simulations show good agreement for resonance frequency and quality factor for the three studied modes. © 2016 IOP Publishing Ltd.
Hydrodynamic and hydromagnetic stability
Chandrasekhar, S
1981-01-01
Dr. Chandrasekhar's book received high praise when it first appeared in 1961 as part of Oxford University Press' International Series of Monographs on Physics. Since then it has been reprinted numerous times in its expensive hardcover format. This first lower-priced, sturdy paperback edition will be welcomed by graduate physics students and scientists familiar with Dr. Chandrasekhar's work, particularly in light of the resurgence of interest in the Rayleigh-Bénard problem. This book presents a most lucid introduction to the Rayleigh-Bénard problem: it has also been applauded for its thorough, clear coverage of the theory of instabilities causing convection. Dr. Chandrasekhar considers most of the typical problems in hydromagnetic stability, with the exception of viscous shear flow; a specialized domain deserving a book unto itself. Contents include: Rotation; Stability of More General Flows; Bénard Problem; Gravitational Equilibrium and Instability; Stability of a Magnetic Field; Thermal Instability of a L...
Squeeze-film flow between a flat impermeable bearing and an anisotropic porous bed
Karmakar, Timir; Raja Sekhar, G. P.
2018-04-01
We consider a theoretical model of the squeeze film in the presence of a porous bed. The gap between the porous bed and the bearing is assumed to be filled with a Newtonian fluid. We use the Navier-Stokes equation in the fluid region and the Darcy equation in the fluid filled porous region. Lubrication approximation is used to derive the corresponding evolution equation for the film thickness. We use G. S. Beavers and D. D. Joseph ["Boundary conditions at a naturally permeable wall," J. Fluid. Mech. 30, 197-207 (1967)] and M. Le Bars and M. G. Worster ["Interfacial conditions between a pure fluid and a porous medium: Implications for binary alloy solidification," J. Fluid. Mech. 550, 149-173 (2006)] condition at the liquid porous interface and present a detailed analysis on the corresponding impact. We assume that the porous bed is anisotropic in nature with permeabilities K2 and K1 along the principal axes. Accordingly, the anisotropic angle ϕ is taken as the angle between the horizontal direction and principal axis with permeability K2. We show that the anisotropic permeability ratio and the anisotropic angle make a significant influence on the contact time, flux, velocity, etc. Contact time to meet the porous bed when a bearing approaches under a constant prescribed load is estimated. We present some important findings (relevant to the knee joint) based on the anisotropic properties of the human cartilage. For a prescribed constant load, we have estimated the time duration, during which a healthy human knee remains fluid lubricated.
The effect of air entrapment on the performance of squeeze film dampers: Experiments and analysis
Diaz Briceno, Sergio Enrique
Squeeze film dampers (SFDs) are an effective means to introduce the required damping in rotor-bearing systems. They are a standard application in jet engines and are commonly used in industrial compressors. Yet, lack of understanding of their operation has confined the design of SFDs to a costly trial and error process based on prior experience. The main factor deterring the success of analytical models for the prediction of SFDs' performance lays on the modeling of the dynamic film rupture. Usually, the cavitation models developed for journal bearings are applied to SFDs. Yet, the characteristic motion of the SFD results in the entrapment of air into the oil film, thus producing a bubbly mixture that can not be represented by these models. In this work, an extensive experimental study establishes qualitatively and---for the first time---quantitatively the differences between operation with vapor cavitation and with air entrainment. The experiments show that most operating conditions lead to air entrainment and demonstrate the paramount effect it has on the performance of SFDs, evidencing the limitation of currently available models. Further experiments address the operation of SFDs with controlled bubbly mixtures. These experiments bolster the possibility of modeling air entrapment by representing the lubricant as a homogeneous mixture of air and oil and provide a reliable data base for benchmarking such a model. An analytical model is developed based on a homogeneous mixture assumption and where the bubbles are described by the Rayleigh-Plesset equation. Good agreement is obtained between this model and the measurements performed in the SFD operating with controlled mixtures. A complementary analytical model is devised to estimate the amount of air entrained from the balance of axial flows in the film. A combination of the analytical models for prediction of the air volume fraction and of the hydrodynamic pressures renders promising results for prediction of the
Novikov, Dmitrii K.; Diligenskii, Dmitrii S.
2018-01-01
The article considers the work of some squeeze film damper with elastic rings parts. This type of damper is widely used in gas turbine engines supports. Nevertheless, modern analytical solutions have a number of limitations. The article considers the behavior of simple hydrodynamic damping systems. It describes the analysis of fluid-solid interaction simulation applicability for the defying properties of hydrodynamic damper with elastic rings (“allison ring”). There are some recommendations on the fluid structural interaction analysis of the hydrodynamic damper with elastic rings.
Stochastic acceleration by hydromagnetic turbulence
International Nuclear Information System (INIS)
Kulsrud, R.M.
1979-03-01
A general theory for particle acceleration by weak hydromagnetic turbulence with a given spectrum of waves is described. Various limiting cases, corresponding to Fermi acceleration and magnetic pumping, are discussed and two numerical examples illustrating them are given. An attempt is made to show that the expression for the rate of Fermi acceleration is valid for finite amplitudes
Directory of Open Access Journals (Sweden)
H. P. Jagadish
2013-01-01
Full Text Available Squeeze film dampers are novel rotor dynamic devices used to alleviate small amplitude, large force vibrations and are used in conjunction with antifriction bearings in aircraft jet engine bearings to provide external damping as these possess very little inherent damping. Electrorheological (ER fluids are controllable fluids in which the rheological properties of the fluid, particularly viscosity, can be controlled in accordance with the requirements of the rotor dynamic system by controlling the intensity of the applied electric field and this property can be utilized in squeeze film dampers, to provide variable stiffness and damping at a particular excitation frequency. The paper investigates the effect of temperature and electric field on the apparent viscosity and dynamic (stiffness and damping characteristics of ER fluid (suspension of diatomite in transformer oil using the available literature. These characteristics increase with the field as the viscosity increases with the field. However, these characteristics decrease with increase in temperature and shear strain rate as the viscosity of the fluid decreases with temperature and shear strain rate. The temperature is an important parameter as the aircraft jet engine rotors are located in a zone of high temperature gradients and the damper fluid is susceptible to large variations in temperature.
Czech Academy of Sciences Publication Activity Database
Zapoměl, Jaroslav; Ferfecki, P.; Forte, P.
2017-01-01
Roč. 52, December (2017), s. 558-575 ISSN 0307-904X R&D Projects: GA ČR GA15-06621S Institutional support: RVO:61388998 Keywords : magnetorheological squeeze film damper * bilinear material * stability of computational procedures * Bingham theoretical material Subject RIV: JR - Other Machinery OBOR OECD: Mechanical engineering Impact factor: 2.350, year: 2016
Czech Academy of Sciences Publication Activity Database
Hlaváček, Miroslav
2000-01-01
Roč. 33, č. 11 (2000), s. 1415-1422 ISSN 0021-9290 R&D Projects: GA ČR GA103/00/0008 Keywords : human ankle joint * squeeze-film lubrication * synovial fluid filtration * worn-out cartilage superficial zone Subject RIV: BK - Fluid Dynamics Impact factor: 1.474, year: 2000
Study of squeeze film damping in a micro-beam resonator based on micro-polar theory
Directory of Open Access Journals (Sweden)
Mina Ghanbari
Full Text Available In this paper, squeeze film damping in a micro-beam resonator based on micro-polar theory has been investigated. The proposed model for this study consists of a clamped-clamped micro-beam bounded between two fixed layers. The gap between the micro-beam and layers is filled with air. As fluid behaves differently in micro scale than macro, the micro-scale fluid field in the gap has been modeled based on micro-polar theory. Equation of motion governing transverse deflection of the micro- beam based on modified couple stress theory and also non-linear Reynolds equation of the fluid field based on micropolar theory have been non-dimensionalized, linearized and solved simultaneously in order to calculate the quality factor of the resonator. The effect of micropolar parameters of air on the quality factor has been investigated. The quality factor of the of the micro-beam resonator for different values of non-dimensionalized length scale of the beam, squeeze number and also non-dimensionalized pressure has been calculated and compared to the obtained values of quality factor based on classical theory.
International Nuclear Information System (INIS)
Zubairy, Suhail
2005-01-01
Quantum squeezed states are a consequence of uncertainty relations; a state is squeezed when the noise in one variable is reduced below the symmetric limit at the expense of the increased noise in the conjugate variable such that the Heisenberg uncertainty relation is not violated. Such states have been known since the earliest days of quantum mechanics. The realization in the early 80's that quantum squeezed states of the radiation field can have important applications in high precision Michelson interferometry for detecting gravitational waves led to a tremendous amount of activity, both in theoretical and experimental quantum optics. The present volume, edited by two eminent scientists, is a collection of papers by leading experts in the field of squeezed states on different aspects of the field as it stands today. The book is divided into three parts. In the first part, there are three articles that review the fundamentals. The first paper by Knight and Buzek presents an introductory account of squeezed states and their properties. The chapter, which opens with the quantization of the radiation field, goes on to discuss the quantum optical properties of single mode and multimode squeezed states. The second article by Hillery provides a detailed description of field quantization in the presence of a nonlinear dielectric medium, thus providing a rigorous treatment of squeezing in nonlinear media. The third article by Yurke presents a comprehensive discussion of the input-output theory of the squeezed radiation at the dielectric boundaries. The second part of the book, comprising of three articles, deals with the generation of squeezed states. In the first article, Drummond reviews the squeezing properties of light in nonlinear systems such as parametric oscillators. He also discusses squeezed light propagation through waveguides and optical fibers. In the second article, Ralph concentrates on active laser sources of squeezing and presents an analysis based on the
Hydromagnetic theory of solar sectors: slow hydromagnetic waves
International Nuclear Information System (INIS)
Suess, S.T.
1975-01-01
Magnetic sectors on the sun are a feature, when the solar dipole field is subtracted, reminiscent of grapefruit sections in terms of the boundaries described by the magnetic field polarity change. One possible suggestion for the origin of these sectors is that they are hydromagnetic waves controlled by the rotation, toroidal magnetic field, and stratification within the convection zone of the sun. The merits of this suggestion are evaluated with respect to the observations and a specific theoretical model. 4 figs, 38 refs. (U.S.)
Damping of the radial impulsive motion of LMFBR core components separated by fluid squeeze films
International Nuclear Information System (INIS)
Liebe, R.; Zehlein, H.
1977-01-01
The core deformation of a liquid metal cooled fast breeder reactor (LMFBR) due to local pressure propagation from rapid energy releases is a complex three-dimensional fluid-structure-interaction problem. High pressure transients of short duration cause structural deformation of the closely spaced fuel elements, which are surrounded by the flowing coolant. Corresponding relative displacements give rise to squeezing fluid motion in the thin layers between the subassemblies. Therefore significant backpressures are produced and the resulting time and space dependent fluid forces are acting on the structure as additional non-conservative external loads. Realistic LMFBR safety analysis of several clustered fuel elements have to account for such flow induced forces. Several idealized models have been proposed to study some aspects of the complex problem. As part of the core mechanics activities at GfK Karlsruhe this paper describes two fluid flow models (model A, model B), which are shown to be suitable for physically coupled fluid-structure analyses. Important assumptions are discussed in both cases and basic equations are derived for one- and two-dimensional incompressible flow fields. The interface of corresponing computer codes FLUF (model A) and FLOWAX (model B) with structural dynamics programs is outlined. Finally fluid-structure interaction problems relevant to LMFBR design are analyzed; parametric studies indicate a significant cushioning effect, energy dissipation and a strongly nonlinear as well as timedependent damping of the structural response. (Auth.)
Directory of Open Access Journals (Sweden)
M. E. Shimpi
2012-01-01
Full Text Available Efforts have been directed to study and analyze the squeeze film performance between rotating transversely rough curved porous annular plates in the presence of a magnetic fluid lubricant considering the effect of elastic deformation. A stochastic random variable with nonzero mean, variance, and skewness characterizes the random roughness of the bearing surfaces. With the aid of suitable boundary conditions, the associated stochastically averaged Reynolds' equation is solved to obtain the pressure distribution in turn, which results in the calculation of the load-carrying capacity. The graphical representations establish that the transverse roughness, in general, adversely affects the performance characteristics. However, the magnetization registers a relatively improved performance. It is found that the deformation causes reduced load-carrying capacity which gets further decreased by the porosity. This investigation tends to indicate that the adverse effect of porosity, standard deviation and deformation can be compensated to certain extent by the positive effect of the magnetic fluid lubricant in the case of negatively skewed roughness by choosing the rotational inertia and the aspect ratio, especially for suitable ratio of curvature parameters.
Directory of Open Access Journals (Sweden)
Martin Gugat
2012-05-01
Full Text Available Compressible squeeze film damping is a phenomenon of great importance for micromachines. For example, for the optimal design of an electrostatically actuated micro-cantilever mass sensor that operates in air, it is essential to have a model for the system behavior that can be evaluated efficiently. An analytical model that is based upon a solution of the linearized Reynolds equation has been given by R.B. Darling. In this paper we explain how some infinite sums that appear in Darling’s model can be evaluated analytically. As an example of applications of these closed form representations, we compute an approximation for the critical frequency where the spring component of the reaction force on the microplate, due to the motion through the air, is equal to a certain given multiple of the damping component. We also show how some double series that appear in the model can be reduced to a single infinite series that can be approximated efficiently.
Basic Technology of Squeeze-Film Dampers for Rotor Dynamics Control.
1981-11-01
rs. ’lhis is he we’er in part due ice t ll omission ,i t ir\\- atare ice Ie , -ir, inth-re-nti.al ’elh,-itv prfile ly the .liicrt I .5 + = -h Il - e...bearing film. If surface way be related to the physical chemistry of the lubricant, and sliding is in the direction ot gap divergence, then the pressure
A Macro Model of Squeeze-Film Air Damping in the Free-Molecule Regime
Hong, Gang; Ye, Wenjing
2009-01-01
An accurate macro model for free‐molecule squeeze‐film air damping on micro plate resonators is present. This model relates air damping directly with device dimensions and operation parameters and therefore provides an efficient tool for the design of high‐performance micro resonators. The construction of the macro model is based on Molecular Dynamics (MD) simulations and analytical traveling‐time distribution. Its accuracy is validated via the comparison between the calculated quality factors of several micro resonators and the available experimental measurements and full MD simulation results. It has been found that the relative errors of the quality factors of two resonators, as compared with experimental data, are 3.9% and 5.7% respectively. The agreements between the macro model results and MD simulation results, on the other hand, are excellent in all cases considered.
A Macro Model of Squeeze-Film Air Damping in the Free-Molecule Regime
Hong, Gang
2009-11-30
An accurate macro model for free‐molecule squeeze‐film air damping on micro plate resonators is present. This model relates air damping directly with device dimensions and operation parameters and therefore provides an efficient tool for the design of high‐performance micro resonators. The construction of the macro model is based on Molecular Dynamics (MD) simulations and analytical traveling‐time distribution. Its accuracy is validated via the comparison between the calculated quality factors of several micro resonators and the available experimental measurements and full MD simulation results. It has been found that the relative errors of the quality factors of two resonators, as compared with experimental data, are 3.9% and 5.7% respectively. The agreements between the macro model results and MD simulation results, on the other hand, are excellent in all cases considered.
International Nuclear Information System (INIS)
Piteau, Philippe; Antunes, Jose
2012-01-01
Squeeze film dynamical effects are relevant in many industrial contexts, bearings and seals being the most conspicuous applications, but also in other industrial contexts, for instance when dealing with the seismic excitation of spent fuel racks. The significant nonlinearity of the squeeze-film forces which arise prevents the use of linearized flow models, and a fully nonlinear formulation must be used for adequate computational predictions. Because it can easily accommodate both laminar and turbulence flow effects, a simplified bulk-flow model based on gap-averaged Navier-Stokes equations, incorporating all relevant inertial and dissipative terms was previously developed by the authors, assuming a constant skin-friction coefficient. In this paper we develop an improved theoretical formulation, where the dependence of the friction coefficient on the local flow velocity is explicitly accounted for, such that it can be applied to laminar, turbulent and mixed flows. Numerical solutions for both the basic and improved nonlinear one-dimensional time-domain formulations are presented in the paper. Furthermore, we present and discuss the results of an extensive series of experiments performed at CEA/Saclay, which were performed on a test rig consisting on a long gravity-driven instrumented plate of rectangular shape colliding with a planar surface. Theoretical results stemming from both theoretical flow models are confronted with the experimental measurements, in order to assert the strengths and drawbacks of the simpler original model, as well as the improvements brought by the new but more involved flow formulation. (authors)
Proctor, Margaret P.; Gunter, Edgar J.
2007-01-01
A case study of a high-speed seal test rotor shows how rotor dynamic analysis can be used to diagnose the source of high vibrations and evaluate a proposed remedy. Experimental results are compared with the synchronous and non-synchronous whirl response analysis of a double overhung, high-speed seal test rotor with ball bearings supported in 5.84- and 12.7-mm-long, un-centered squeeze-film oil dampers. Test performance with the original damper of length 5.84 mm was marginal. Non-synchronous whirling occurred at the overhung seal test disk and there was a high amplitude synchronous response near the drive spline above 32,000 rpm. Nonlinear synchronous unbalance and time transient whirl studies were conducted on the seal test rotor with the original and extended damper lengths. With the original damper design, the nonlinear synchronous response showed that unbalance could cause damper lockup at 33,000 rpm. Alford cross-coupling forces were also included at the overhung seal test disk for the whirl analysis. Sub-synchronous whirling at the seal test disk was observed in the nonlinear time transient analysis. With the extended damper length of 12.7 mm, the sub-synchronous motion was eliminated and the rotor unbalance response was acceptable to 45,000 rpm with moderate rotor unbalance. Seal test rotor orbits and vibration levels with the extended squeeze film dampers showed smooth operation to 40,444 rpm.
Hydromagnetic wave coupling in the magnetosphere
International Nuclear Information System (INIS)
Lee, D.
1990-01-01
The hydromagnetic wave phenomena in the magnetosphere has been an area of space physics and plasma physics where theory has been successful in explaining many features in satellite experiments and ground-based observations. Magnetohydrodynamic (MHD) waves, which are composed of transverse Alven waves and compressional waves, are usually coupled in space due to an inhomogeneous plasma density and curved magnetic field lines. In addition to these effects, hot temperature plasmas invoke various ultra low frequency (ULF) wave phenomena via macroscopic wave instabilities or wave particle resonant interactions. These properties of the coupling between the two different MHD waves were analytically and numerically studied in a simplified model such as the box model with straight field lines. However, the real magnetosphere is rather close to a dipole field, even though the night side of the magnetosphere is significantly distorted from dipole geometry. The curvature of field lines plays an important role in understanding hydromagnetic wave coupling in the magnetosphere since the MHD wave propagation depends strongly on the curved magnetic fields. The study of the hydromagnetic wave properties on an inhomogeneous and curved magnetic field system by considering realistic geometry is emphasized. Most of the current theories are reviewed and a number of observations are introduced according to the wave excitation mechanism. Studies are also performed with the development of numerical models such as the two and three dimensional MHD dipole models. An attempt is made to understand and classify the hydromagnetic wave behavior in inhomogeneous and hot plasmas with respect to the energy sources and their frequency band in the magnetosphere. Therefore, various excitation mechanisms for hydromagnetic waves are examined to compare analytical and numerical results with the observations
Hydromagnetic thin film flow: Linear stability
Amaouche, Mustapha; Ait Abderrahmane, Hamid; Bourdache, Lamia
2013-01-01
. The linear stability of the problem is investigated, and the influence of electromagnetic field on the flow stability is analyzed. Two cases are considered: the applied magnetic field is either normal or parallel to the fluid flow direction, while
DEFF Research Database (Denmark)
Sivebæk, Ion Marius; Persson, Bo N. J.
2016-01-01
in the more disordered regions between these domains. The short alkanes stay fluid-like during the entire squeeze out process which result in a very small squeeze-out pressure which is almost constant during the squeeze-out of the last monolayer of the fluid. In all cases we observe lubricant trapped...
Studying fluid squeeze characteristics for aerostatic journal bearing
International Nuclear Information System (INIS)
Abdel-Rahman, Gamal M.
2008-01-01
The Reynolds equation for studying fluid squeeze of aerostatic journal bearing is solved numerically by considering the quasi-steady behavior of the air film. The radial displacement can influence the air film thickness modifying the pressure distribution in the journal-bearing gap. Also, the variations in the seal characteristics with eccentricity, time, squeeze number, length-to-diameter and supply pressure are presented. The numerical results for the squeeze load-carrying capacity are given in a non-dimensional form
Hydromagnetic rotational braking of magnetic stars
International Nuclear Information System (INIS)
Fleck, R.C. Jr.
1980-01-01
It is suggested that the magnetic Ap stars can be rotationally decelerated to long periods by the braking action of the associated magnetic field on time scales of order 10 7 --10 10 years depending on whether the star's dipole field is aligned perpendicular or parallel to the rotation axis. Rotation includes a toroidal magnetic field in the plasma surrounding a star, and the accompanying magnetic stresses produce a net torque acting to despin the star. These results indicate that it is not necessary to postulate mass loss or mass accretion for this purely hydromagnetic braking effect
International Nuclear Information System (INIS)
Chang-Jian, C.-W.; Chen, C.-K.
2008-01-01
This study presents a dynamic analysis of a flexible rotor supported by two porous squeeze couple stress fluid film journal bearings with non-linear suspension. The dynamics of the rotor center and bearing center are studied. The analysis of the rotor-bearing system is investigated under the assumptions of non-Newtonian fluid and a short bearing approximation. The spatial displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The numerical results show that the stability of the system varies with the non-dimensional speed ratios, the non-dimensional parameter l* and the permeability. The modeling results thus obtained by using the method proposed in this paper can be employed to predict the stability of the rotor-bearing system and the undesirable behavior of the rotor and bearing center can be avoided
Directory of Open Access Journals (Sweden)
Jimit R Patel
2014-12-01
Full Text Available Efforts have been made to analyze the Shliomis model based ferrofluid lubrication of a squeeze film between rotating rough curved circular plates where the upper plate has a porous facing. Different models of porosity are treated. The stochastic modeling of Christensen and Tonder has been employed to evaluate the effect of surface roughness. The related stochastically averaged Reynolds type equation is numerically solved to obtain the pressure distribution, leading to the calculation of load carrying capacity. The results presented in graphical form establish that the Kozeny-Carman model is more favorable as compared to the Irmay one from the design point of view. It is observed that the Shliomis model based ferrofluid lubrication performs relatively better than the Neuringer-Rosensweig one. Although the bearing suffers due to transverse surface roughness, with a suitable choice of curvature parameters and rotational ratio, the negative effect of porosity and standard deviation can be minimized by the ferrofluid lubrication at least in the case of negatively skewed roughness.
Thermal radiation effects on hydromagnetic flow
International Nuclear Information System (INIS)
Abdelkhalek, M.M.
2005-01-01
Numerical results are presented for the effects of thermal radiation, buoyancy and heat generation or absorption on hydromagnetic flow over an accelerating permeable surface. These results are obtained by solving the coupled nonlinear partial differential equations describing the conservation of mass, momentum and energy by a perturbation technique. This qualitatively agrees with the expectations, since the magnetic field exerts a retarding force on the free convection flow. A parametric study is performed to illustrate the influence of the radiation parameter, magnetic parameter, Prandtl number, Grashof number and Schmidt number on the profiles of the velocity components and temperature. The effects of the different parameters on the velocity and temperature profiles as well as the skin friction and wall heat transfer are presented graphically. Favorable comparisons with previously published work confirm the correctness of numerical results
Hydromagnetic turbulence in the direct interaction approximation
International Nuclear Information System (INIS)
Nagarajan, S.
1975-01-01
The dissertation is concerned with the nature of turbulence in a medium with large electrical conductivity. Three distinct though inter-related questions are asked. Firstly, the evolution of a weak, random initial magnetic field in a highly conducting, isotropically turbulent fluid is discussed. This was first discussed in the paper 'Growth of Turbulent Magnetic Fields' by Kraichnan and Nagargian. The Physics of Fluids, volume 10, number 4, 1967. Secondly, the direct interaction approximation for hydromagnetic turbulence maintained by stationary, isotropic, random stirring forces is formulated in the wave-number-frequency domain. Thirdly, the dynamical evolution of a weak, random, magnetic excitation in a turbulent electrically conducting fluid is examined under varying kinematic conditions. (G.T.H.)
Bloch, Anthony M.; Rojo, Alberto G.
2000-01-01
In this paper we consider the classical and quantum control of squeezed states of harmonic oscillators. This provides a method for reducing noise below the quantum limit and provides an example of the control of under-actuated systems in the stochastic and quantum context. We consider also the interaction of a squeezed quantum oscillator with an external heat bath.
Heat and mass transfer in the unsteady hydromagnetic free ...
African Journals Online (AJOL)
Heat and mass transfer in the unsteady hydromagnetic free-convection flow in a rotating binary fluid I. ... By imposing a time dependent perturbation on the constant plate temperature and concentration and assuming a differential approximation for the radiative flux, the coupled non linear problem is solved for the ...
Hydromagnetic perturbations due to localized flows: An eddy theorem
International Nuclear Information System (INIS)
Bird, J.F.
1979-01-01
The hydromagnetic far-field generated by localized regions of incompressible flow of electrically conducting media in uniform magnetic fields is derived explicitly in terms of the spin angular momentum of the flow. Some applications and a corollary result for bounded media are given
Knox, D. J.; Wilson, S. K.; Duffy, B. R.; McKee, S.
2013-01-01
surface moving under a prescribed constant load and a flat thin porous bed coating a stationary flat impermeable surface is considered. Unlike in the classical case of an impermeable bed, in which an infinite time is required for the two surfaces to touch
Properties of squeezed Schroedinger cats
International Nuclear Information System (INIS)
Obada, A.S.F.; Omar, Z.M.
1995-09-01
In this article we investigate some statistical properties of the even and odd squeezed (squeezed Schroedinger cat) states. The quasi-probability distribution functions especially W(α) and Q(α) are calculated and discussed for these states. The phase distribution function is discussed. A generation scheme is proposed for either the squeezed generalized Schroedinger cat, or the squeezed number state. (author). 35 refs, 5 figs
Spin squeezing and quantum correlations
Indian Academy of Sciences (India)
2 states. A coherent spin-s state. (CSS) θ φ can then be thought of as having no quantum correlations as the constituent. 2s elementary spins point in the same direction ˆn(θ φ) which is the mean spin direction. 2. State classification and squeezing. In order to discuss squeezing, we begin with the squeezing condition itself.
International Nuclear Information System (INIS)
Chizhov, A.V.; Paris, M.G.A.
1998-01-01
Phase squeezed states of a single mode radiation field have been introduced as eigenstates of a linear combination of lowering and raising operators. The explicit expression in the Fock basis has been obtained and some relevant properties have been illustrated. (author)
Thermalization of squeezed states
International Nuclear Information System (INIS)
Solomon, Allan I
2005-01-01
Starting with a thermal squeezed state defined as a conventional thermal state based on an appropriate Hamiltonian, we show how an important physical property, the signal-to-noise ratio, is degraded, and propose a simple model of thermalization (Kraus thermalization)
Hydromagnetic stability of rotating stratified compressible fluid flows
Energy Technology Data Exchange (ETDEWEB)
Srinivasan, V; Kandaswamy, P [Dept. of Mathematics, Bharathiar University, Coimbatore, Tamil Nadu, India; Debnath, L [Dept. of Mathematics, University of Central Florida, Orlando, USA
1984-09-01
The hydromagnetic stability of a radially stratified compressible fluid rotating between two coaxial cylinders is investigated. The stability with respect to axisymmetric disturbances is examined. The fluid system is found to be thoroughly stable to axisymmetric disturbances provided the fluid rotates very rapidly. The system is shown to be unstable to non-axisymmetric disturbances, and the slow amplifying hydromagnetic wave modes propagate against the basic rotation. The lower and upper bounds of the azimuthal phase speeds of the amplifying waves are determined. A quadrant theorem on the slow waves characteristic of a rapidly rotating fluid is derived. Special attention is given to the effects of compressibility of the fluid. Some results concerning the stability of an incompressible fluid system are obtained as special cases of the present analysis.
Hydromagnetic modes in an inhomogeneous collisionless plasma of finite pressure
International Nuclear Information System (INIS)
Klimushkin, D.Yu.
2006-01-01
One studied three-dimensional structure and rate of growth of hydromagnetic waves. The mode is shown to be the Alfven modified inhomogeneity, finite pressure and plasma anisotropy. The mode structure transverse the magnetic shells may be of two types. Under some specific conditions one may observe image-drift waves in the magnetosphere. The described modes may be responsible for some types of geomagnetic field oscillations [ru
Hydromagnetic waves, turbulence, and collisionless processes in the interplanetary medium
International Nuclear Information System (INIS)
Barnes, A.
1983-01-01
The solar wind does not flow quietly. It seethes and undulates, fluctuating on time scales that range from the solar rotation period down to fractions of milliseconds. Most of the power in interplanetary waves and turbulence lies at hydromagnetic scales. These fluctuations are normally of large amplitude, containing enough energy to affect solar and galactic cosmic rays, and may be the remnants of a coronal turbulence field powerful enough to play a major role in accelerating the solar wind itself. The origin and evolution of interplanetary hydromagnetic waves and turbulence, and their influence on the large-scale dynamics of the solar wind are among the most fundamental questions of solar-terrestrial physics. First hydrodynamic waves and turbulences in the interplanetary medium are discussed in two sections, respectively. Because the length and time scales for hydromagnetic fluctuations are very much smaller than the corresponding Coulomb collision scales of the plasma ions and electrons, the interplanetary variations are modelled as fluctuations in a magnetohydrodynamic fluid. In the last section, collisionless phenomena are discussed. They are of qualitative significance. (Auth.)
Correlation measurement of squeezed light
DEFF Research Database (Denmark)
Krivitsky, Leonid; Andersen, Ulrik Lund; Dong, R.
2009-01-01
We study the implementation of a correlation measurement technique for the characterization of squeezed light which is nearly free of electronic noise. With two different sources of squeezed light, we show that the sign of the covariance coefficient, revealed from the time-resolved correlation data......, is witnessing the presence of squeezing in the system. Furthermore, we estimate the degree of squeezing using the correlation method and compare it to the standard homodyne measurement scheme. We show that the role of electronic detector noise is minimized using the correlation approach as opposed to homodyning...
Shear flow stabilization of the hydromagnetic Rayleigh-Taylor instability
International Nuclear Information System (INIS)
Roderick, N.F.; Shumlak, U.; Douglas, M.; Peterkin, R.E. Jr.; Ruden, E.
1997-01-01
Numerical simulations have indicated that shear flow may help stabilize the hydromagnetic Rayleigh-Taylor instability in imploding plasma z-pinches. A simple extension to a model presented in Chandrasekhar has been developed to study the linear stability of incompressible plasma subjected to both a shear flow and acceleration. The model has been used to investigate the stability plasma implosion schemes using externally imposed velocity shear which develops from the plasma flow itself. Specific parameters were chosen to represent plasma implosions driven by the Saturn and PBFA-Z, pulsed power generators at Sandia National Laboratories. Results indicate a high shear is necessary to stabilize the z-pinch implosions studied
The effect of lower-hybrid waves on the propagation of hydromagnetic waves
International Nuclear Information System (INIS)
Hamabata, Hiromitsu; Namikawa, Tomikazu; Mori, Kazuhiro
1988-01-01
Propagation characteristics of hydromagnetic waves in a magnetic plasma are investigated using the two-plasma fluid equations including the effect of lower-hybrid waves propagating perpendicularly to the magnetic field. The effect of lower-hybrid waves on the propagation of hydromagnetic waves is analysed in terms of phase speed, growth rate, refractive index, polarization and the amplitude relation between the density perturbation and the magnetic-field perturbation for the cases when hydromagnetic waves propagate in the plane whose normal is perpendicular to both the magnetic field and the propagation direction of lower-hybrid waves and in the plane perpendicular to the propagation direction of lower-hybrid waves. It is shown that hydromagnetic waves propagating at small angles to the propagation direction of lower-hybrid waves can be excited by the effect of lower-hybrid waves and the energy of excited waves propagates nearly parallel to the propagation direction of lower-hybrid waves. (author)
Krupp, N.; Tsurutani, B. T.; Lanzerotti, L. J.; Maclennan, C. G.
1996-01-01
We report on measurements of energetic particle modulations observed by the HI-SCALE instrument aboard the Ulysses Spacecraft that were associated with the only hydromagnetic wave event measured inside the Jovian magnetosphere by the Ulysses magnetometer investigation.
Supersqueezed states from squeezed states
International Nuclear Information System (INIS)
Nieto, M.M.
1992-01-01
Using super-Baker-Campbell-Hausdorff relations on the elements of the supergroup OSP(2/2), we derive the supersqueeze operator and the supersqueezed states, which are the supersymmetric generalization of the squeezed states of the harmonic oscillator
Qutrit squeezing via semiclassical evolution
International Nuclear Information System (INIS)
Klimov, Andrei B; Dinani, Hossein Tavakoli; Medendorp, Zachari E D; Guise, Hubert de
2011-01-01
We introduce a concept of squeezing in collective qutrit systems through a geometrical picture connected to the deformation of the isotropic fluctuations of su(3) operators when evaluated in a coherent state. This kind of squeezing can be generated by Hamiltonians nonlinear in the generators of su(3) algebra. A simplest model of such a nonlinear evolution is analyzed in terms of semiclassical evolution of the SU(3) Wigner function. (paper)
CERN Bulletin
2012-01-01
Rare processes like the Higgs production require maximizing the number of proton collisions. This is done by squeezing the beams to very small sizes. However, interesting physics processes also happen when beams are not squeezed at interaction points. Last week, a dedicated run showed that the LHC is a record-breaking machine also with de-squeezed beams. This figure shows an online hit map of one of the ATLAS/ALFA detectors. The narrow elliptical shape is the typical signal produced by elastically scattered protons. The removal of the background (central bulge) is a challenge for both experiments. The beam squeezing parameter is known by experts as beta-star (ß*): the smaller the ß*, the stronger the squeezing. To obtain as many collisions as possible in the heart of the experiments, the ß* at full energy is 0.60 m – that is, beams are squeezed to very small beam sizes. This maximizes the rate of proton collisions as required for rare process...
Hydromagnetic instabilities and magnetic field amplification in core collapse supernovae
Energy Technology Data Exchange (ETDEWEB)
Cerda-Duran, P; Obergaulinger, M; Mueller, E [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-st. 1, 85748 Garching (Germany); Aloy, M A; Font, J A, E-mail: cerda@mpa-garching.mpg.de [Departamento de Astronomia y Astrofisica, Universidad de Valencia, 46100 Burjassot, Valencia (Spain)
2011-09-22
Some of the most violent events in the universe, the gamma ray burst, could be related to the gravitational collapse of massive stellar cores. The recent association of long GRBs to some class of type Ic supernova seems to support this view. In such scenario fast rotation, strong magnetic fields and general relativistic effects are key ingredients. It is thus important to understand the mechanism that amplifies the magnetic field under that conditions. I present global simulations of the magneto-rotational collapse of stellar cores in general relativity and semi-global simulations of hydromagnetic instabilities under core collapse conditions. I discuss effect of the magneto-rotational instability and the magnetic field amplification during the collapse, the uncertainties in this process and the dynamical effects in the supernova explosion.
Numerical treatment of the unsteady hydromagnetic thermal boundary layer problem
International Nuclear Information System (INIS)
Drymonitou, M.A.; Geroyannis, V.S.; Goudas, C.L.
1980-01-01
This paper presents a suitable numerical method for the treatment of the unsteady hydromagnetic thermal boundary layer problem for flows past an infinite porous flat plate, the motion of which is governed by a general time-dependent law, under the influence of a transverse externally set magnetic field. The normal velocity of suction/injection at the plate is also assumed to be time-dependent. The results obtained on the basis of numerical approximations seem to compare favourably with earlier results (Pande et al., 1976; Tokis, 1978). Analytical approximations are given for the cases of a plate (i) generally accelerated and (ii) harmonically oscillating. The direct numerical treatment is obviously advantageous since it allows handling of cases where the known methods for analytical approximations are not applicable. This problem is closely related to the motions and heat transfer occurring locally on the surfaces of stars. (orig.)
Nonlinear radiative peristaltic flow of hydromagnetic fluid through porous medium
Hussain, Q.; Latif, T.; Alvi, N.; Asghar, S.
2018-06-01
The radiative heat and mass transfer in wall induced flow of hydromagnetic fluid through porous medium in an asymmetric channel is analyzed. The fluid viscosity is considered temperature dependent. In the theory of peristalsis, the radiation effects are either ignored or taken as linear approximation of radiative heat flux. Such approximation is only possible when there is sufficiently small temperature differences in the flow field; however, nonlinear radiation effects are valid for large temperature differences as well (the new feature added in the present study). Mathematical modeling of the problems include the complicated system of highly nonlinear differential equations. Semi-analytical solutions are established in the wave reference frame. Results are displayed graphically and discussed in detail for the variation of various physical parameters with the special attention to viscosity, radiation, and temperature ratio parameters.
Nonlinear radiative peristaltic flow of hydromagnetic fluid through porous medium
Directory of Open Access Journals (Sweden)
Q. Hussain
2018-06-01
Full Text Available The radiative heat and mass transfer in wall induced flow of hydromagnetic fluid through porous medium in an asymmetric channel is analyzed. The fluid viscosity is considered temperature dependent. In the theory of peristalsis, the radiation effects are either ignored or taken as linear approximation of radiative heat flux. Such approximation is only possible when there is sufficiently small temperature differences in the flow field; however, nonlinear radiation effects are valid for large temperature differences as well (the new feature added in the present study. Mathematical modeling of the problems include the complicated system of highly nonlinear differential equations. Semi-analytical solutions are established in the wave reference frame. Results are displayed graphically and discussed in detail for the variation of various physical parameters with the special attention to viscosity, radiation, and temperature ratio parameters. Keywords: Nonlinear thermal radiation, Variable viscosity, Porous medium, Soret and Dufour effects, Peristalsis
On the stability of certain collisional configurations of hydromagnetic flows
Energy Technology Data Exchange (ETDEWEB)
Nunez, Manuel, E-mail: mnjmhd@am.uva.e [Departamento de Analisis Matematico, Universidad de Valladolid, 47005 Valladolid (Spain)
2010-09-06
We study the flow of a hydromagnetic fluid toward an obstacle in two different cases: when this is a rigid wall or when two plasma masses collide with each other. The magnetic field far from the obstacle is assumed to be aligned with the flow. The diffusivity is taken as low, and a boundary layer approach for the stationary MHD system is considered. The relevant equations turn out to be a generalization of the Falkner-Skan ones, and while analytical solutions are impossible to obtain, a qualitative analysis shows that whenever the size of the Alfven speed far from the interface exceeds the size of the fluid velocity, the system has no nontrivial solutions. The interpretation of this is that in this case disturbances occurring in the boundary layer travel upstream and disturb the boundary conditions at the outer layers.
What are squeezed states really like
International Nuclear Information System (INIS)
Nieto, M.M.
1984-01-01
The simple harmonic oscillator and some quantum mechanics are reviewed. Then a special case of the squeezed states, the coherent states, is discussed. Next, the coherent states are described from the operator formalism. The squeezed states are described from the Schroedinger point of view, and their properties are discussed. Harmonic motion and coherent and squeezed states are discussed for general potentials. Then the (harmonic oscillator) squeezed states are discussed from the operator point of view and some of their mathematical properties
Squeezed light in optomechanical systems
DEFF Research Database (Denmark)
Harris, G. I.; Taylor, M. A.; Hoff, Ulrich Busk
2012-01-01
Squeezed light enhanced optomechanical measurements are demonstrated in both intra-cavity and biological contexts, with respective enhancements of 1.0 and 2.7 dB. Quantum enhanced microrheology of the cytoplasm of a yeast cell is thereby realized.......Squeezed light enhanced optomechanical measurements are demonstrated in both intra-cavity and biological contexts, with respective enhancements of 1.0 and 2.7 dB. Quantum enhanced microrheology of the cytoplasm of a yeast cell is thereby realized....
Squeezed colour states in gluon jet
Kilin, S. YA.; Kuvshinov, V. I.; Firago, S. A.
1993-01-01
The possibility of the formation of squeezed states of gluon fields in quantum chromodynamics due to nonlinear nonperturbative self interaction during jet evolution in the process of e(+)e(-) annihilation into hadrons, which are analogous to the quantum photon squeezed states in quantum electrodynamics, is demonstrated. Additionally, the squeezing parameters are calculated.
30 years of squeezed light generation
DEFF Research Database (Denmark)
Andersen, Ulrik Lund; Gehring, Tobias; Marquardt, Christoph
2016-01-01
Squeezed light generation has come of age. Significant advances on squeezed light generation have been made over the last 30 years—from the initial, conceptual experiment in 1985 till today’s top-tuned, application-oriented setups. Here we review the main experimental platforms for generating...... quadrature squeezed light that have been investigated in the last 30 years....
Squeezing via two-photon transitions
Savage, C. M.; Walls, D. F.
1986-05-01
The squeezing spectrum for a cavity field mode interacting with an ensemble of three-level 'Lambda-configuration' atoms by an effective two-photon transition is calculated. The advantage of the three-level Lambda system as a squeezing medium, that is, optical nonlinearity without atomic saturation, has recently been pointed out by Reid, Walls, and Dalton. Perfect squeezing is predicted at the turning points for dispersive optical bistability and good squeezing for a range of other cases. Three-level ladder atoms interacting by an effective two-photon transition are also shown to give perfect squeezing in the dispersive limit.
Non-Markovian reservoir-dependent squeezing
International Nuclear Information System (INIS)
Paavola, J
2010-01-01
The squeezing dynamics of a damped harmonic oscillator are studied for different types of environment without making the Markovian approximation. The squeezing dynamics of a coherent state depend on the reservoir spectrum in a unique way that can, in the weak coupling approximation, be analysed analytically. Comparison of squeezing dynamics for ohmic, sub-ohmic and super-ohmic environments is done, showing a clear connection between the squeezing-non-squeezing oscillations and reservoir structure. Understanding the effects occurring due to structured reservoirs is important both from a purely theoretical point of view and in connection with evolving experimental techniques and future quantum computing applications.
Classification of hydromagnetic emissions based on frequency--time spectra
International Nuclear Information System (INIS)
Fukunishi, H.; Toya, T.; Koike, K.; Kuwashima, M.; Kawamura, M.
1981-01-01
By using 3035 hydromagnetic emission events observed in the frequency range of 0.1--2.0 Hz at Syowa (Lapprox.6), HM emissions have been classified into eight subtypes based on their spectral structures, i.e., HM whistler, periodic HM emission, HM chorus, HM emission burst, IPDP, morning IPDP, Pc 1--2 band, and irregular HM emission. It is seen that each subtype has a preferential magnetic local time interval and also a frequency range for its occurrence. Morning IPDP events and irregular HM emissions occur in the magnetic morning hours, while dispersive periodic HM emissions and HM emission bursts occur around magnetic local noon, then HM chorus emissions occur in the afternoon hours and IPDP events occur in the evening hours. Furthermore, it is noticed that the mid-frequencies of these emissions vary from high frequencies in the morning hours to low frequencies in the afternoon hours. On the basis of these results, the generation mechanisms of each subtype are discussed
Studies of hydromagnetic waves and oscillations in plasmas
International Nuclear Information System (INIS)
Sawley, M.L.
1980-10-01
Small amplitude magnetoacoustic oscillations in a partially ionized, non-uniform, current carrying plasma column of finite beta are considered. The linearized magnetohydrodynamic equations are used to develop a theory describing both free and forced magnetoacoustic oscillations. The results of numerical calculations are given for the specific case of diffuse pinch equilibrium configurations. In an experimental study the amplitude of the oscillating axial magnetic flux is determined for several frequencies in the vicinity of the first magnetoacoustic resonance. Accurate determination of the plasma density profile is shown to be possible. Finite-amplitude effects on the propagation of axisymmetric hydromagnetic waves are examined. A nonlinear theory is developed which describes the second-order perturbation that accompanies the primary wave. The influence of Hall currents and the presence of neutral atoms on the second-order fields is treated. In an investigation on the propagation of torsional waves the observed second-order fields are shown to exhibit good quantitative agreement with theoretical calculations for moderate primary wave amplitudes. The re-ionization of the plasma by a torsional wave is investigated. A theoretical description is given of the nonlinear excitation of magnetoacoustic oscillations by means of an oscillating axial current
Energy Technology Data Exchange (ETDEWEB)
Longacre, R. S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Physics Dept.
2016-09-01
Squeeze out happen when the expanding central fireball flows around a large surface flux tube in a central Au-Au collision at RHIC. We model such an effect in a flux tube model. Two particle correlations with respect to the v_{2} axis formed by the soft fireball particles flowing around this large flux tube is a way of measuring the effect.
Couette flow of a hydro-magnetic electrically conducting fluid with ...
African Journals Online (AJOL)
Numerical solution of the problem of Couette flow of a hydromagnetic electrically conducting fluid has been obtained where the temperature of the fluid is assumed to vary exponentially. Results obtained for the flow velocity, temperature, skin friction and rate of heat transfer indicate that the temperature is higher when the ...
Possibilities of heating a TFR plasma by absorption of the fast hydromagnetic wave
International Nuclear Information System (INIS)
Adam, J.
The prospects of TFR heating by fast hydromagnetic waves are considered by an examination of the following topics: (1) characteristics of the dispersion relation, (2) the charge impedance of an antenna capable of exciting these modes, and (3) the heating effects which would be caused by dissipation of these waves around ω = ω/sub ci/ and ω = 2ω/sub ci/
Short-cavity squeezing in barium
Hope, D. M.; Bachor, H-A.; Manson, P. J.; Mcclelland, D. E.
1992-01-01
Broadband phase sensitive noise and squeezing were experimentally observed in a system of barium atoms interacting with a single mode of a short optical cavity. Squeezing of 13 +/- 3 percent was observed. A maximum possible squeezing of 45 +/- 8 percent could be inferred for out experimental conditions, after correction for measured loss factors. Noise reductions below the quantum limit were found over a range of detection frequencies 60-170 MHz and were best for high cavity transmission and large optical depths. The amount of squeezing observed is consistent with theoretical predictions from a full quantum statistical model of the system.
Institute of Scientific and Technical Information of China (English)
Zhang Jing-Tao; He Guang-Qiang; Ren Li-Jie; Zeng Gui-Hua
2011-01-01
This paper investigates an analytical expression of teleportation fidelity in the teleportation scheme of a single mode of electromagnetic field. The fidelity between the original squeezed coherent state and the teleported one is expressed in terms of the squeezing parameter r and the quantum channel parameter (two-mode squeezed state) p. The results of analysis show that the fidelity increases with the increase of the quantum channel parameter p, while the fidelity decreases with the increase of the squeezing parameter r of the squeezed state. Thus the coherent state (r = 0)is the best quantum signal for continuous variable quantum teleportation once the quantum channel is built.
DEFF Research Database (Denmark)
Tartaglino, Ugo; Sivebæk, Ion Marius; Persson, B N J
2006-01-01
layers develop in the lubricant film when the width is of the order of a few atomic diameters. The branched isobutane forms more disordered structures which permit it to stay liquidlike at smaller surface separations. During squeezing the solvation forces show oscillations corresponding to the width...... of a molecule. At low speeds (interfacial) squeezing velocity in most practical applications is very low when the lubricant layer has molecular thickness, one expects n-butane to be a better boundary lubricant than...
Teleportation of Squeezed Entangled State
Institute of Scientific and Technical Information of China (English)
HU Li-Yun; ZHOU Nan-Run
2007-01-01
Based on the coherent entangled state |α, x＞ we introduce the squeezed entangled state (SES). Then we propose a teleportation protocol for the SES by using Einstein-Podolsky-Rosen entangled state |η＞as a quantum channel.The calculation is greatly simplified by virtue of the Schmidt decompositions of both |α, x＞and |η＞. Any bipartite states that can be expanded in terms of |α, x＞may be teleported in this way due to the completeness of |α, x＞.
Parsing polarization squeezing into Fock layers
DEFF Research Database (Denmark)
Mueller, Christian R.; Madsen, Lars Skovgaard; Klimov, Andrei B.
2016-01-01
photon number do the methods coincide; when the photon number is indefinite, we parse the state in Fock layers, finding that substantially higher squeezing can be observed in some of the single layers. By capitalizing on the properties of the Husimi Q function, we map this notion onto the Poincare space......, providing a full account of the measured squeezing....
Workshop on Squeezed States and Uncertainty Relations
International Nuclear Information System (INIS)
Han, D.; Kim, Y.S.; Zachary, W.W.
1992-02-01
The proceedings from the workshop are presented, and the focus was on the application of squeezed states. There are many who say that the potential for industrial applications is enormous, as the history of the conventional laser suggests. All those who worked so hard to produce squeezed states of light are continuing their efforts to construct more efficient squeezed-state lasers. Quite naturally, they are looking for new experiments using these lasers. The physical basis of squeezed states is the uncertainty relation in Fock space, which is also the basis for the creation and annihilation of particles in quantum field theory. Indeed, squeezed states provide a unique opportunity for field theoreticians to develop a measurement theory for quantum field theory
Toward a compact fibered squeezing parametric source.
Brieussel, Alexandre; Ott, Konstantin; Joos, Maxime; Treps, Nicolas; Fabre, Claude
2018-03-15
In this work, we investigate three different compact fibered systems generating vacuum squeezing that involve optical cavities limited by the end surface of a fiber and by a curved mirror and containing a thin parametric crystal. These systems have the advantage to couple squeezed states directly to a fiber, allowing the user to benefit from the flexibility of fibers in the use of squeezing. Three types of fibers are investigated: standard single-mode fibers, photonic-crystal large-mode-area single-mode fibers, and short multimode fibers taped to a single-mode fiber. The observed squeezing is modest (-0.56 dB, -0.9 dB, -1 dB), but these experiments open the way for miniaturized squeezing devices that could be a very interesting advantage in scaling up quantum systems for quantum processing, opening new perspectives in the domain of integrated quantum optics.
On field line resonances of hydromagnetic Alfven waves in dipole magnetic field
International Nuclear Information System (INIS)
Chen, Liu; Cowley, S.C.
1989-07-01
Using the dipole magnetic field model, we have developed the theory of field line resonances of hydromagnetic Alfven waves in general magnetic field geometries. In this model, the Alfven speed thus varies both perpendicular and parallel to the magnetic field. Specifically, it is found that field line resonances do persist in the dipole model. The corresponding singular solutions near the resonant field lines as well as the natural definition of standing shear Alfven eigenfunctions have also been systematically derived. 11 refs
Coherent and squeezed states in phase space
International Nuclear Information System (INIS)
Jannussis, A.; Bartzis, V.; Vlahos, E.
1990-01-01
In the present paper, the coherent and the squeezed states in phase space have been studied. From the wave functions of the coherent and the squeezed state, their corresponding Wigner distribution functions are calculated. Especially the calculation of the corresponding Wigner functions for the above states permits the determination of the mean values of position and momentum and thus the Heisenberg uncertainty relation. In fact, from the related results, it is concluded that the uncertainty relation of the coherent and associated squeezed states is the same
Quantum nondemolition squeezing of a nanomechanical resonator
Ruskov, Rusko; Schwab, Keith; Korotkov, Alexander
2005-03-01
We discuss squeezing of the nanoresonator state produced by periodic measurement of position by a quantum point contact or a single-electron transistor. The mechanism of squeezing is the stroboscopic quantum nondemolition measurement generalized to the case of continuous measurement by a weakly coupled detector. The magnitude of squeezing is calculated for the harmonic and stroboscopic modulations of measurement, taking into account detector efficiency and nanoresonator quality factor. We also analyze the operation of the quantum feedback, which prevents fluctuations of the wavepacket center due to measurement back-action. Verification of the squeezed state can be performed in almost the same way as its preparation; similar procedure can also be used for the force detection with sensitivity beyond the standard quantum limit.
Magnon squeezing states in a ferromagnet
International Nuclear Information System (INIS)
Wang Junfeng; Cheng Ze; Ping Yunxia; Wan Jinyin; Zhang Yanmin
2006-01-01
In this Letter we discuss squeezing state of magnon in ferromagnet, which permits a reduction in the quantum fluctuation of the spin component to below the zero-point quantum noise level of coherent magnon states. We investigate the generation of squeezed magnon state through calculating the expectation values of spin component fluctuation. The mean field theory is introduced in dealing with the nonlinear interaction terms of Hamiltonian of magnon system
Waveguide quantum electrodynamics in squeezed vacuum
You, Jieyu; Liao, Zeyang; Li, Sheng-Wen; Zubairy, M. Suhail
2018-02-01
We study the dynamics of a general multiemitter system coupled to the squeezed vacuum reservoir and derive a master equation for this system based on the Weisskopf-Wigner approximation. In this theory, we include the effect of positions of the squeezing sources which is usually neglected in the previous studies. We apply this theory to a quasi-one-dimensional waveguide case where the squeezing in one dimension is experimentally achievable. We show that while dipole-dipole interaction induced by ordinary vacuum depends on the emitter separation, the two-photon process due to the squeezed vacuum depends on the positions of the emitters with respect to the squeezing sources. The dephasing rate, decay rate, and the resonance fluorescence of the waveguide-QED in the squeezed vacuum are controllable by changing the positions of emitters. Furthermore, we demonstrate that the stationary maximum entangled NOON state for identical emitters can be reached with arbitrary initial state when the center-of-mass position of the emitters satisfies certain conditions.
Squeezed States in Josephson Junctions.
Hu, X.; Nori, F.
1996-03-01
We have studied quantum fluctuation properties of Josephson junctions in the limit of large Josephson coupling energy and small charging energy, when the eigenstates of the system can be treated as being nearly localized. We have considered(X. Hu and F. Nori, preprints.) a Josephson junction in a variety of situations, e.g., coupled to one or several of the following elements: a capacitor, an inductor (in a superconducting ring), and an applied current source. By solving an effective Shrödinger equation, we have obtained squeezed vacuum (coherent) states as the ground states of a ``free-oscillating'' (linearly-driven) Josephson junction, and calculated the uncertainties of its canonical momentum, charge, and coordinate, phase. We have also shown that the excited states of the various systems we consider are similar to the number states of a simple harmonic oscillator but with different fluctuation properties. Furthermore, we have obtained the time-evolution operators for these systems. These operators can make it easier to calculate the time-dependence of the expectation values and fluctuations of various quantities starting from an arbitrary initial state.
LHC Report: Freshly squeezed beams!
Mike Lamont for the LHC Team
2011-01-01
After careful validation of new machine settings, the LHC was ready for higher luminosity operation. New luminosity records have been set, but the operations team continues to wrestle with machine availability issues. The commissioning of the squeeze to a ß* of 1 m in ATLAS and CMS described in the last Bulletin took until Wednesday, 7 September to complete. In order to validate the new set-up, beam losses were provoked in a controlled way with low intensity beams. The distribution of beam loss around the machine in these tests is known as a loss map. The loss maps showed that the collimation system is catching the large majority of beam losses as it should, and that the machine was ready for us to ramp the number of bunches back up and go to physics production. The ramp-up of the number of bunches went smoothly with fills at 264, 480, and 912 bunches on the way back to the machine’s previous record of 1380 bunches (first fill on Friday, 9 Se...
The Second International Workshop on Squeezed States and Uncertainty Relations
Han, D. (Editor); Kim, Y. S.; Manko, V. I.
1993-01-01
This conference publication contains the proceedings of the Second International Workshop on Squeezed States and Uncertainty Relations held in Moscow, Russia, on 25-29 May 1992. The purpose of this workshop was to study possible applications of squeezed states of light. The Workshop brought together many active researchers in squeezed states of light and those who may find the concept of squeezed states useful in their research, particularly in understanding the uncertainty relations. It was found at this workshop that the squeezed state has a much broader implication than the two-photon coherent states in quantum optics, since the squeeze transformation is one of the most fundamental transformations in physics.
Energy Technology Data Exchange (ETDEWEB)
Isa, Sharena Mohamad; Ali, Anati [Department of Mathematical Sciences, Faculty of Science Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia sharena-ina@yahoo.com, anati@utm.my (Malaysia)
2015-10-22
In this paper, the hydromagnetic flow of dusty fluid over a vertical stretching sheet with thermal radiation is investigated. The governing partial differential equations are reduced to nonlinear ordinary differential equations using similarity transformation. These nonlinear ordinary differential equations are solved numerically using Runge-Kutta Fehlberg fourth-fifth order method (RKF45 Method). The behavior of velocity and temperature profiles of hydromagnetic fluid flow of dusty fluid is analyzed and discussed for different parameters of interest such as unsteady parameter, fluid-particle interaction parameter, the magnetic parameter, radiation parameter and Prandtl number on the flow.
Coupled hydromagnetic wave excitation and ion acceleration upstream of the earth's bow shock
International Nuclear Information System (INIS)
Lee, M.A.
1982-01-01
A self-consistent theory is presented for the excitation of hydromagnetic waves and the acceleration of diffuse ions upstream of the earth's bow shock in the quasi-equilibrium that results when the solar wind velocity and the interplanetary magnetic field are nearly parallel. For the waves the quasi-equilibrium results from a balance between excitation by the ions, which stream relative to the solar wind plasma, and convective loss to the magnetosheath. For the diffuse ions the quasi-equilibrium results from a balance between injection at the shock front, confinement to the foreshock by pitch angle scattering on the waves, acceleration by compression at the shock front, loss to the magnetosheath, loss due to escape upstream of the foreshock, and loss via diffusion perpendicular to the average magnetic field onto field lines that do not connect to the shock front. Diffusion equations describing the ion transport and wave kinetic equations describing the hydromagnetic wave transport are solved self-consistently to yield analytical expressions for the differential wave intensity spectrum as a function of frequency and distance from the bow shock z and for the ion omnidirectional distribution functions and anisotropies as functions of energy and z, In quantitative agreement with observations, the theory predicts (1) exponential spectra at the bow shock in energy per charge, (2) a decrease in intensity and hardening of the ion spectra with increasing z, (3) a 30-keV proton anisotropy parallel to z increasing from -0.28 at the bow shock to +0.51 as z→infinity (4) a linearly polarized wave intensity spectrum with a minimum at approx.6 x 10 -3 Hz and a maximum at approx.2--3 x 10 -2 Hz, (5) a decrease in the wave intensity spectrum with increasing z, (6) a total energy density in protons with energies >15 keV about eight times that in the hydromagnetic waves
Relationship between squeezing and entangled state transformations
Fan Hong Yi
2003-01-01
We show that c-number dilation transform in the Einstein-Podolsky-Rosen (EPR) entangled state, i.e. vertical bar eta sub 1 , eta sub 2) -> vertical bar eta sub 1 , eta sub 2 /mu) (or vertical bar eta sub 1 , eta sub 2) -> vertical bar eta sub 1 /mu, eta sub 2)), maps onto a kind of one-sided two-mode squeezing operator exp left brace i lambda/2(P sub 1 + P sub 2)(Q sub 1 + Q sub 2) - lambda/2 right brace, (or exp left brace i lambda/2(P sub 1 - P sub 2)(Q sub 1 - Q sub 2) - lambda/2 right brace). Using the IWOP technique, we derive their normally ordered form and construct the corresponding squeezed states. In doing so, some new relationship between squeezing and entangled state transformation is revealed. The dynamic Hamiltonian for such a kind of squeezing evolution is derived. The properties and application of the one-sided squeezed state are briefly discussed. These states can also be obtained with the use of a beam splitter.
Versatile Gaussian probes for squeezing estimation
Rigovacca, Luca; Farace, Alessandro; Souza, Leonardo A. M.; De Pasquale, Antonella; Giovannetti, Vittorio; Adesso, Gerardo
2017-05-01
We consider an instance of "black-box" quantum metrology in the Gaussian framework, where we aim to estimate the amount of squeezing applied on an input probe, without previous knowledge on the phase of the applied squeezing. By taking the quantum Fisher information (QFI) as the figure of merit, we evaluate its average and variance with respect to this phase in order to identify probe states that yield good precision for many different squeezing directions. We first consider the case of single-mode Gaussian probes with the same energy, and find that pure squeezed states maximize the average quantum Fisher information (AvQFI) at the cost of a performance that oscillates strongly as the squeezing direction is changed. Although the variance can be brought to zero by correlating the probing system with a reference mode, the maximum AvQFI cannot be increased in the same way. A different scenario opens if one takes into account the effects of photon losses: coherent states represent the optimal single-mode choice when losses exceed a certain threshold and, moreover, correlated probes can now yield larger AvQFI values than all single-mode states, on top of having zero variance.
LHC Report: Preparing for a tighter squeeze
Jan Uythoven for the LHC Team
2011-01-01
The LHC is resuming operation after a planned period of machine development followed by a technical stop. The beams returned last Friday, in the evening of 2 September, and preparations are now being made to squeeze the beams further at the collision points, aiming for new luminosity records. To obtain as many collisions as possible in the heart of the experiments, the beams are squeezed to very small beam sizes. The beam squeezing parameter is known by experts as beta-star: the smaller the ß*, the stronger the squeezing. During the machine development period that started on 24 August, tests were made for the high-luminosity experiments ATLAS and CMS with ß* values of 1 m instead of the 1.5 m used previously. Unfortunately these tests were only partially successful, as some of the beam was lost during the squeezing process. It is thought that the beam losses were caused by the collimators, which were moved closer to the beam, and by the reduced crossing angle of the beams at ...
Effect of wall conductances on hydromagnetic flow and heat transfer in a rotating channel
International Nuclear Information System (INIS)
Mazumder, B.S.
1977-01-01
Wall conductance effects on the hydromagnetic flow and heat transfer between two parallel plates in a rotating frame of reference has been studied when the liquid is permeated by a transverse magnetic field. An exact solution of the governing equation has been obtained. It is found that the velocity current density and the temperature depend only on the sum of the wall conductances phi 1 + phi 2 = phi but magnetic field depends on the individual values of phi 1 and phi 2 where phi 1 and phi 2 are respectively the wall conductance ratios of the upper and lower walls. (Auth.)
Hall effects on hydromagnetic flow of an Oldroyd 6-constant fluid between concentric cylinders
International Nuclear Information System (INIS)
Rana, M.A.; Siddiqui, A.M.; Qamar, Rashid
2009-01-01
The hydromagnetic flow of an electrically conducting, incompressible Oldroyd 6-constant fluid between two concentric cylinders is investigated. The flow is generated by moving inner cylinder and/or application of the constant pressure gradient. Two non-linear boundary value problems are solved numerically. The effects of material parameters, pressure gradient, magnetic field and Hall parameter on the velocity are studied. The graphical representation of velocity reveals that characteristics for shear thinning/shear thickening behaviour of a fluid is dependent upon the rheological properties
Hall effects on hydromagnetic flow of an Oldroyd 6-constant fluid between concentric cylinders
Energy Technology Data Exchange (ETDEWEB)
Rana, M.A. [Management Information System, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)], E-mail: mafzalrana@yahoo.com; Siddiqui, A.M. [Department of Mathematics, Pennsylvania State University, York Campus, York, PA 17403 (United States); Qamar, Rashid [Management Information System, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)
2009-01-15
The hydromagnetic flow of an electrically conducting, incompressible Oldroyd 6-constant fluid between two concentric cylinders is investigated. The flow is generated by moving inner cylinder and/or application of the constant pressure gradient. Two non-linear boundary value problems are solved numerically. The effects of material parameters, pressure gradient, magnetic field and Hall parameter on the velocity are studied. The graphical representation of velocity reveals that characteristics for shear thinning/shear thickening behaviour of a fluid is dependent upon the rheological properties.
Squeezed State Caused by Inverse of Photon Creation Operator
International Nuclear Information System (INIS)
Xu Xuefen
2006-01-01
Using the photon creation operator's eigenstate theory we derive the normally ordered expansion of inverse of the squeezed creation operator. It turns out that using this operator a kind of excitation on the squeezed vacuum states can be formed.
Minimum uncertainty and squeezing in diffusion processes and stochastic quantization
Demartino, S.; Desiena, S.; Illuminati, Fabrizo; Vitiello, Giuseppe
1994-01-01
We show that uncertainty relations, as well as minimum uncertainty coherent and squeezed states, are structural properties for diffusion processes. Through Nelson stochastic quantization we derive the stochastic image of the quantum mechanical coherent and squeezed states.
Secure quantum key distribution using squeezed states
International Nuclear Information System (INIS)
Gottesman, Daniel; Preskill, John
2001-01-01
We prove the security of a quantum key distribution scheme based on transmission of squeezed quantum states of a harmonic oscillator. Our proof employs quantum error-correcting codes that encode a finite-dimensional quantum system in the infinite-dimensional Hilbert space of an oscillator, and protect against errors that shift the canonical variables p and q. If the noise in the quantum channel is weak, squeezing signal states by 2.51 dB (a squeeze factor e r =1.34) is sufficient in principle to ensure the security of a protocol that is suitably enhanced by classical error correction and privacy amplification. Secure key distribution can be achieved over distances comparable to the attenuation length of the quantum channel
Photon statistics, antibunching and squeezed states
International Nuclear Information System (INIS)
Leuchs, G.
1986-01-01
This paper attempts to describe the status and addresses future prospects of experiments regarding photon antibunching, and squeezed states. Light correlation is presented in the framework of classical electrodynamics. The extension to quantized radiation fields is discussed and an introduction to the basic principles related to photon statistics, antibunching and squeezed states are presented. The effect of linear attenuation (beam splitters, neutral density filters, and detector quantum efficiency) on the detected signal is discussed. Experiments on the change of photon statistics by the nonlinear interaction of radiation fields with matter are described and some experimental observations of antibunching and sub-Poissonian photon statistics in resonance fluorescence and with possible schemes for the generation and detection of squeezed states are examined
Planar quantum squeezing and atom interferometry
Energy Technology Data Exchange (ETDEWEB)
He, Q. Y.; Drummond, P. D.; Reid, M. D. [ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia); Peng Shiguo [Department of Physics, Tsinghua University, Beijing 100084 (China)
2011-08-15
We obtain a lower bound on the sum of two orthogonal spin component variances in a plane. This gives a planar uncertainty relation which holds even when the Heisenberg relation is not useful. We investigate the asymptotic, large-J limit and derive the properties of the planar quantum squeezed states that saturate this uncertainty relation. These states extend the concept of spin squeezing to any two conjugate spin directions. We show that planar quantum squeezing can be achieved experimentally as the ground state of a Bose-Einstein condensate in two coupled potential wells with a critical attractive interaction. These states reduce interferometric phase noise at all phase angles simultaneously. This is useful for one-shot interferometric phase measurements where the measured phase is completely unknown. Our results can also be used to derive entanglement criteria for multiple spins J at separated sites, with applications in quantum information.
Spatially single-mode source of bright squeezed vacuum
Pérez, A. M.; Iskhakov, T. Sh.; Sharapova, P.; Lemieux, S.; Tikhonova, O. V.; Chekhova, M. V.; Leuchs, G.
2014-01-01
Bright squeezed vacuum, a macroscopic nonclassical state of light, can be obtained at the output of a strongly pumped non-seeded traveling-wave optical parametric amplifier (OPA). By constructing the OPA of two consecutive crystals separated by a large distance we make the squeezed vacuum spatially single-mode without a significant decrease in the brightness or squeezing.
Demonstration of deterministic and high fidelity squeezing of quantum information
DEFF Research Database (Denmark)
Yoshikawa, J-I.; Hayashi, T-; Akiyama, T.
2007-01-01
, and an ancillary squeezed vacuum state, thus direct interaction between a strong pump and the quantum state is circumvented. We demonstrate three different squeezing levels for a coherent state input. This scheme is highly suitable for the fault-tolerant squeezing transformation in a continuous variable quantum...... computer....
Multiphoton states and amplitude k-th power squeezing
International Nuclear Information System (INIS)
Buzek, V.; Jex, I.
1991-01-01
On the basis of the work of d'Ariano and coworkers a new type of multiphoton states is introduced. Amplitude k-th power squeezing of the multiphoton states are analysed. In particular, it is shown that even if the multiphoton states do not exhibit ordinary squeezing they can be amplitude k-th power squeezed
Stochastic line motion and stochastic flux conservation for nonideal hydromagnetic models
International Nuclear Information System (INIS)
Eyink, Gregory L.
2009-01-01
We prove that smooth solutions of nonideal (viscous and resistive) incompressible magnetohydrodynamic (MHD) equations satisfy a stochastic law of flux conservation. This property implies that the magnetic flux through a surface is equal to the average of the magnetic fluxes through an ensemble of surfaces advected backward in time by the plasma velocity perturbed with a random white noise. Our result is an analog of the well-known Alfven theorem of ideal MHD and is valid for any value of the magnetic Prandtl number. A second stochastic conservation law is shown to hold at unit Prandtl number, a random version of the generalized Kelvin theorem derived by Bekenstein and Oron for ideal MHD. These stochastic conservation laws are not only shown to be consequences of the nonideal MHD equations but are proved in fact to be equivalent to those equations. We derive similar results for two more refined hydromagnetic models, Hall MHD and the two-fluid plasma model, still assuming incompressible velocities and isotropic transport coefficients. Finally, we use these results to discuss briefly the infinite-Reynolds-number limit of hydromagnetic turbulence and to support the conjecture that flux conservation remains stochastic in that limit.
Hydromagnetic flow and radiative heat transfer of nanofluid past a vertical plate
Directory of Open Access Journals (Sweden)
B. Ganga
2017-11-01
Full Text Available Hydromagnetic flow of an incompressible viscous nanofluid past a vertical plate in the presence of thermal radiation is investigated both analytically and numerically. The radiative heat flux is described by the Rosseland diffusion approximation in the energy equation. The governing non-linear partial differential equations are converted into a set of ordinary differential equations by suitable similarity transformations. The resulting ordinary differential equations are successfully solved analytically with the help of homotopy analysis method and numerically by the fourth order RungeâKutta method with shooting technique. The effects of various physical parameters are analyzed and discussed in graphical and tabular forms. The effects of some physical parameters such as Lewis number, Prandtl number, buoyancy ratio, thermophoresis, Brownian motion, radiation parameter and magnetic parameter are analyzed on the velocity, temperature and solid volume fraction profiles as well as on the reduced Nusselt number and the local Sherwood number. An excellent agreement is observed between present analytical and numerical results. Keywords: Nanofluid, Hydromagnetic, Homotopy analysis method, Vertical plate and thermal radiation
Destabilization of hydromagnetic drift-Alfven waves in a finite pressure collisional plasma
International Nuclear Information System (INIS)
Tang, J.T.
1974-01-01
In a finite beta (β = 8πn 0 kT 0 /B 0 2 ) plasma, where the plasma pressure n 0 kT 0 is an appreciable fraction of the confining magnetic field energy-density B 0 2 /8π, density-gradient driven drift waves couple with Alfven waves when the phase velocities of the two waves become comparable. The resulting hydromagnetic drift-Alfven waves separate into two branches--a drift mode and an Alfven mode, with both modes exhibiting magnetic field and localized density fluctuations near the coupling point. The dispersion relation of the collisional drift-Alfven wave is derived by using a slab-geometry, two-fluid model which includes finite beta, electron-ion collisions, ion-ion collisions, finite ion larmar radius, temperature fluctuations, and an axial electron current. A hydromagnetic drift mode is found to be unstable in a moderately dense plasma. A localized ''Alfven'' mode is destabilized only with the passage of an axial current along the plasma column. In order to check the theoretical predictions an experiment is performed in a finite-beta plasma of density n 0 = 10 13 -10 15 cm -3 and temperature T/sub e/ approximately T/sub i/ = 1-7 eV. (U.S.)
Experimental Generation of Multimode Squeezing in an Optical Parametric Amplifier
International Nuclear Information System (INIS)
Liu Kui; Cui Shu-Zhen; Yang Rong-Guo; Zhang Jun-Xiang; Gao Jiang-Rui
2012-01-01
We experimentally demonstrate that HG 01 (Hermit—Gauss) and HG 10 squeezed states can be generated simultaneously in an optical parametric amplifier. The HG 01 mode is a bright squeezed state and the HG 10 mode is a vacuum squeezed state. The squeezing of the HG 01 mode is −2.8 dB, and the squeezing of the HG 10 mode is −1.6 dB. We also demonstrate that the output field is also continuous-variable entanglement with orbital angular momentum. (general)
Squeezing of Collective Excitations in Spin Ensembles
DEFF Research Database (Denmark)
Kraglund Andersen, Christian; Mølmer, Klaus
2012-01-01
We analyse the possibility to create two-mode spin squeezed states of two separate spin ensembles by inverting the spins in one ensemble and allowing spin exchange between the ensembles via a near resonant cavity field. We investigate the dynamics of the system using a combination of numerical an...
Squeezing more from a quantum nondemolition measurement
DEFF Research Database (Denmark)
Buchler, B.C.; Lam, P.K.; Bachor, H.A.
2002-01-01
We use a stable, 5 dB, amplitude squeezed source for a quantum nondomolition (QND) experiment. The performance of our QND system is enhanced by an electro-optic feedforward loop which improve,, the signal transfer efficiency. At best, we measure a total signal transfer of 1.81 and conditional var...
Squeezing-enhanced optomechanical transduction sensitivity
DEFF Research Database (Denmark)
Hoff, Ulrich Busk; Harris, Glen I.; Madsen, Lars Skovgaard
2013-01-01
mechanical systems. Following the proposal of Caves we have experimentally proven the applicability of squeezed light-enhanced interferometric displacement detection in the domain of micromechanical oscillators. The technique has previously been demonstrated for table-top interferometer setups and GW...
Quantum teleportation of entangled squeezed vacuum states
Institute of Scientific and Technical Information of China (English)
蔡新华
2003-01-01
An optical scheme for probabilistic teleporting entangled squeezed vacuum states (SVS) is proposed. In this scheme,the teleported state is a bipartite entangled SVS,and the quantum channel is a tripartite entangled SVS.The process of the teleportation is achieved by using a 50/50 symmetric beamsplitter and photon detectors with the help of classical information.
Tubes, Mono Jets, Squeeze Out and CME
Energy Technology Data Exchange (ETDEWEB)
Longacre, R. [Brookhaven National Lab. (BNL), Upton, NY (United States)
2017-10-23
Glasma Flux Tubes, Mono Jets with squeeze out flow around them plus the Chiral Magnetic Effect(CME) are physical phenomenon that generate two particle correlation with respect to the reaction plane in mid-central 20% to 30% Au-Au collision √sNN = 200.0 GeV measured at RHIC.
Squeezing corrections to the Bloch equations
International Nuclear Information System (INIS)
Abundo, M.; Accardi, L.
1991-01-01
The general analysis of quantum noise shows that a squeezing noise can produce quadratic nonlinearities in the Langevin equations leading to the Bloch equations. These quadratic nonlinearities are governed by the imaginary part of the off-diagonal terms of the covariance of the noise (the squeezing terms) and imply a correction to the usual form of the Bloch equations. Here the case of spin-one nuclei subjected to squeezing noises of particular type is studied numerically. It is shown that the corrections to the Bloch equations, suggested by the theory, to the behaviour of the macroscopic nuclear polarization in a scale of times of the order of the relaxation time can be quite substantial. In the equilibrium regime, even if the qualitative behaviour of the system is the same (exponential decay), the numerical equilibrium values predicted by the theory are consistently different from those predicted by the usual Bloch equation. It is suggested that this difference might be used to test experimentally the observable effects of squeezing noises
Deterministic secure communications using two-mode squeezed states
International Nuclear Information System (INIS)
Marino, Alberto M.; Stroud, C. R. Jr.
2006-01-01
We propose a scheme for quantum cryptography that uses the squeezing phase of a two-mode squeezed state to transmit information securely between two parties. The basic principle behind this scheme is the fact that each mode of the squeezed field by itself does not contain any information regarding the squeezing phase. The squeezing phase can only be obtained through a joint measurement of the two modes. This, combined with the fact that it is possible to perform remote squeezing measurements, makes it possible to implement a secure quantum communication scheme in which a deterministic signal can be transmitted directly between two parties while the encryption is done automatically by the quantum correlations present in the two-mode squeezed state
Study of the character of the effect of various squeezing out agents on the squeezing out process
Energy Technology Data Exchange (ETDEWEB)
Begnazarov, T.
1979-01-01
Results are examined of the study of the process of squeezing out petroleum with water with additives of a chemical reagent as a multifactor experiment, carried out in laboratory conditions. The tests were carried out in inactive petroleum of the Mishkin deposits. In the capacity of the squeezing out agents, water, solutions of caustic soda, and acetic acid were used. The basic factors, affecting the process of waterless squeezing out, included porosity, permeability in respect to gas, water saturation, pressure gradient, volume of the injection of the squeezing out agent were selected. The waterless coefficient of squeezing out also shows an effect on the complete coefficient of squeezing out. As a result of the study of the paired connections, corresponding coefficients of the regression equations and correlation coefficient were produced. The difference according to the forms of the connection between the various squeezing out agent were analyzed.
Hydromagnetic flow of third grade nanofluid with viscous dissipation and flux conditions
Energy Technology Data Exchange (ETDEWEB)
Hussain, T. [Faculty of Computing, Mohammad Ali Jinnah University, Islamabad 44000 (Pakistan); Shehzad, S. A., E-mail: ali-qau70@yahoo.com [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Alsaedi, A. [Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)
2015-08-15
This article investigates the magnetohydrodynamic flow of third grade nanofluid with thermophoresis and Brownian motion effects. Energy equation is considered in the presence of thermal radiation and viscous dissipation. Rosseland’s approximation is employed for thermal radiation. The heat and concentration flux conditions are taken into account. The governing nonlinear mathematical expressions of velocity, temperature and concentration are converted into dimensionless expressions via transformations. Series solutions of the dimensionless velocity, temperature and concentration are developed. Convergence of the constructed solutions is checked out both graphically and numerically. Effects of interesting physical parameters on the temperature and concentration are plotted and discussed in detail. Numerical values of skin-friction coefficient are computed for the hydrodynamic and hydromagnetic flow cases.
International Nuclear Information System (INIS)
Roderick, N.F.; Hussey, T.W.; Faehl, R.J.; Boyd, R.W.
1978-01-01
Two-dimensional (r-z) magnetohydrodynamic simulations of the electromagnetic implosion of metallic foil plasmas show, for certain initial configurations, a tendency to develop large-amplitude perturbations characteristic of the hydromagnetic Rayleigh-Taylor instability. These perturbations develop at the plasma magnetic field interface for plasma configurations where the density gradient scale length, the characteristic dimension for the instability, is short. The effects on the plasma dynamics of the implosion will be discussed for several initial foil configurations. In general, the growth rates and linear mode structure are found to be influenced by the plasma shell thickness and density gradient scale length, in agreement with theory. The most destructive modes are found to be those with wavelengths of the order of the plasma shell thickness
Model for the saturation of the hydromagnetic Rayleigh--Taylor instability
International Nuclear Information System (INIS)
Roderick, N.F.; Hussey, T.W.
1984-01-01
The saturation of the hydromagnetic Rayleigh--Taylor instability is caused by the reduction of driving current in the bubble region between the spikes formed as the instability develops. For short wavelengths linear magnetic field diffusion provides the necessary smoothing of the magnetic field to reduce the driving force. For wavelengths longer than the magnetic field diffusion length, the current is shorted through material which expands into the bubble region. This initially low density accumulates in the bubble and eventually provides a source of sufficiently high conductivity plasma which reduces the magnetic field penetration to the front of the bubble. Simple analytic models have been developed to verify and and quantify these predictions. These models have been compared with two-dimensional magnetohydrodynamic calculations for imploding plasma shells and give good agreement with these more detailed simulations
Directory of Open Access Journals (Sweden)
O. D. Makinde
2014-01-01
Full Text Available This paper investigates the unsteady hydromagnetic-free convection of an incompressible electrical conducting Boussinesq’s radiating fluid past a moving vertical plate in an optically thin environment with the Navier slip, viscous dissipation, and Ohmic and Newtonian heating. The nonlinear partial differential equations governing the transient problem are obtained and tackled numerically using a semidiscretization finite difference method coupled with Runge-Kutta Fehlberg integration technique. Numerical data for the local skin friction coefficient and the Nusselt number have been tabulated for various values of parametric conditions. Graphical results for the fluid velocity, temperature, skin friction, and the Nusselt number are presented and discussed. The results indicate that the skin friction coefficient decreases while the heat transfer rate at the plate surface increases as the slip parameter and Newtonian heating increase.
Hydromagnetic nonlinear thermally radiative nanoliquid flow with Newtonian heat and mass conditions
Directory of Open Access Journals (Sweden)
Muhammad Ijaz Khan
Full Text Available This paper communicates the analysis of MHD three-dimensional flow of Jeffrey nanoliquid over a stretchable surface. Flow due to a bidirectional surface is considered. Heat and mass transfer subject to volume fraction of nanoparticles, heat generation and nonlinear solar radiation are examined. Newtonian heat and mass transportation conditions are employed at surface. Concept of boundary layer is utilized to developed the mathematical problem. The boundary value problem is dictated by ten physical parameters: Deborah number, Hartman number, ratio of stretching rates, thermophoretic parameter, Brownian motion parameter, Prandtl number, temperature ratio parameter, conjugate heat and mass parameters and Lewis number. Convergent solutions are obtained using homotopic procedure. Convergence zone for obtained results is explicitly identified. The obtained solutions are interpreted physically. Keywords: Hydromagnetic flow, Viscoelastic nanofluid, Thermophoretic and Brownian moment, Nonlinear thermal radiation, Heat generation
Adaptive phase estimation with squeezed thermal light
DEFF Research Database (Denmark)
Berni, A. A.; Madsen, Lars Skovgaard; Lassen, Mikael Østergaard
2013-01-01
Summary form only given. The use of quantum states of light in optical interferometry improves the precision in the estimation of a phase shift, paving the way for applications in quantum metrology, computation and cryptography. Sub-shot noise phase sensing can for example be achieved by injecting...... investigate the performances of such protocol under the realistic assumption of thermalization of the probe state. Indeed, adaptive phase estimation schemes with squeezed states and Bayesian processing of homodyne data have been shown to be asymptotically optimal in the pure case, thus approaching the quantum...... Cramér-Rao bound. In our protocol we take advantage of the enhanced sensitivity of homodyne detection in proximity of the optimal phase which maximizes the homodyne Fisher information. A squeezed thermal probe state (signal) undergoes an unknown phase shift. The first estimation step involves...
Generalization of the Davydov Ansatz by squeezing
Energy Technology Data Exchange (ETDEWEB)
Grossmann, Frank; Werther, Michael [Institut für Theoretische Physik, Technische Universität Dresden, D-01062 Dresden (Germany); Chen, Lipeng; Zhao, Yang [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)
2016-12-20
We propose an extension of the Davydov Ansatz employing displaced squeezed states in the oscillator Hilbert space. The Dirac–Frenkel variational principle is used to derive the modified equations for the variational parameters. First numerical studies of the dynamics of the spin-boson model with a single bosonic degree of freedom reveal an overall improvement of the results as compared to the standard Davydov Ansatz.
Baryon asymmetry, inflation and squeezed states
International Nuclear Information System (INIS)
Bambah, Bindu A.; Chaitanya, K.V.S. Shiv; Mukku, C.
2007-01-01
We use the general formalism of squeezed rotated states to calculate baryon asymmetry in the wake of inflation through parametric amplification. We base our analysis on a B and CP violating Lagrangian in an isotropically expanding universe. The B and CP violating terms originate from the coupling of complex fields with non-zero baryon number to a complex background inflaton field. We show that a differential amplification of particle and antiparticle modes gives rise to baryon asymmetry
Experimental Realization of a Thermal Squeezed State of Levitated Optomechanics
Rashid, Muddassar; Tufarelli, Tommaso; Bateman, James; Vovrosh, Jamie; Hempston, David; Kim, M. S.; Ulbricht, Hendrik
2016-12-01
We experimentally squeeze the thermal motional state of an optically levitated nanosphere by fast switching between two trapping frequencies. The measured phase-space distribution of the center of mass of our particle shows the typical shape of a squeezed thermal state, from which we infer up to 2.7 dB of squeezing along one motional direction. In these experiments the average thermal occupancy is high and, even after squeezing, the motional state remains in the remit of classical statistical mechanics. Nevertheless, we argue that the manipulation scheme described here could be used to achieve squeezing in the quantum regime if preceded by cooling of the levitated mechanical oscillator. Additionally, a higher degree of squeezing could, in principle, be achieved by repeating the frequency-switching protocol multiple times.
Squeeze flow of a Carreau fluid during sphere impact
Uddin, J.
2012-07-19
We present results from a combined numerical and experimental investigation into the squeeze flow induced when a solid sphere impacts onto a thin, ultra-viscous film of non-Newtonian fluid. We examine both the sphere motion through the liquid as well as the fluid flow field in the region directly beneath the sphere during approach to a solid plate. In the experiments we use silicone oil as the model fluid, which is well-described by the Carreau model. We use high-speed imaging and particle tracking to achieve flow visualisation within the film itself and derive the corresponding velocity fields. We show that the radial velocity either diverges as the gap between the sphere and the wall diminishes (Z tip → 0) or that it reaches a maximum value and then decays rapidly to zero as the sphere comes to rest at a non-zero distance (Z tip = Z min ) away from the wall. The horizontal shear rate is calculated and is responsible for significant viscosity reduction during the approach of the sphere. Our model of this flow, based on lubrication theory, is solved numerically and compared to experimental trials. We show that our model is able to correctly describe the physical features of the flow observed in the experiments.
Squeeze flow of a Carreau fluid during sphere impact
Uddin, J.; Marston, J. O.; Thoroddsen, Sigurdur T
2012-01-01
We present results from a combined numerical and experimental investigation into the squeeze flow induced when a solid sphere impacts onto a thin, ultra-viscous film of non-Newtonian fluid. We examine both the sphere motion through the liquid as well as the fluid flow field in the region directly beneath the sphere during approach to a solid plate. In the experiments we use silicone oil as the model fluid, which is well-described by the Carreau model. We use high-speed imaging and particle tracking to achieve flow visualisation within the film itself and derive the corresponding velocity fields. We show that the radial velocity either diverges as the gap between the sphere and the wall diminishes (Z tip → 0) or that it reaches a maximum value and then decays rapidly to zero as the sphere comes to rest at a non-zero distance (Z tip = Z min ) away from the wall. The horizontal shear rate is calculated and is responsible for significant viscosity reduction during the approach of the sphere. Our model of this flow, based on lubrication theory, is solved numerically and compared to experimental trials. We show that our model is able to correctly describe the physical features of the flow observed in the experiments.
Simulations and experiments on polarization squeezing in optical fiber
DEFF Research Database (Denmark)
Corney, J.F.; Heersink, J.; Dong, R.
2008-01-01
We investigate polarization squeezing of ultrashort pulses in optical fiber, over a wide range of input energies and fiber lengths. Comparisons are made between experimental data and quantum dynamical simulations to find good quantitative agreement. The numerical calculations, performed using both...... effects cause a marked deterioration of squeezing at higher energies and longer fiber lengths. We also calculate the optimum fiber length for maximum squeezing....
Spin squeezing and entanglement in a dispersive cavity
International Nuclear Information System (INIS)
Deb, R. N.; Abdalla, M. Sebawe; Hassan, S. S.; Nayak, N.
2006-01-01
We consider a system of N two-level atoms (spins) interacting with the radiation field in a dispersive but high-Q cavity. Under an adiabatic condition, the interaction Hamiltonian reduces to a function of spin operators which is capable of producing spin squeezing. For a bipartite system (N=2), the expressions for spin squeezing get very simple, giving a clear indication of close to 100% noise reduction. We analyse this squeezing as a measure of bipartite entanglement
A novel method for polarization squeezing with Photonic Crystal Fibers
DEFF Research Database (Denmark)
Milanovic, Josip; Lassen, Mikael Østergaard; Andersen, Ulrik Lund
2010-01-01
Photonic Crystal Fibers can be tailored to increase the effective Kerr nonlinearity, while producing smaller amounts of excess noise compared to standard silicon fibers. Using these features of Photonic Crystal Fibers we create polarization squeezed states with increased purity compared to standa...... Stokes parameter squeezing of −3.9 ±0.3dB and anti-squeezing of 16.2 ±0.3dB....
Crystal-field-modulated magnon squeezing states in a ferromagnet
International Nuclear Information System (INIS)
Peng Feng
2003-01-01
The magnon squeezing states in some magnetic crystals allow a reduction in the quantum fluctuations of the spin component to below the zero-point quantum noise level of the coherent magnon states. It is known that there are the magnon squeezing states in an antiferromagnet. However, their generating mechanism is not suitable for the ferromagnet. In this paper, we discuss the possibility of generating the magnon squeezing states in a ferromagnet, and discuss the effect of the crystal field on the magnon squeezing states
Non-collinear configuration for dichromatic squeezing
Energy Technology Data Exchange (ETDEWEB)
Andreoni, A.; Bondani, M. [Como Univ. (Italy). Dipt. di Scienze Chimiche Fisiche e Matematiche; Mauro D' Ariano, G.; Paris, M.G.A. [Como Univ. (Italy). Dipt. di Scienze Chimiche Fisiche e Matematiche; Quantum Optics Group, Unita INFM and Dipt. di Fisica ' Alessandro Volta' , Univ. di Pavia (Italy)
2001-02-01
We propose a non-collinear experimental scheme for the joint generation of two amplitude-squeezed beams at the frequencies {omega}{sub 1} and {omega}{sub 2}, fundamental and second harmonics of a Nd:YAG laser pulse. The scheme consists of two successive steps, both involving second-order non-linear interactions in {beta}-BaB{sub 2}O{sub 4} non-linear crystals. One of the output beams show subPoissonian photon statistics, and this allows to use photodetection instead of homodyne detection for diagnostics. (orig.)
Non-collinear configuration for dichromatic squeezing
International Nuclear Information System (INIS)
Andreoni, A.; Bondani, M.
2001-01-01
We propose a non-collinear experimental scheme for the joint generation of two amplitude-squeezed beams at the frequencies ω 1 and ω 2 , fundamental and second harmonics of a Nd:YAG laser pulse. The scheme consists of two successive steps, both involving second-order non-linear interactions in β-BaB 2 O 4 non-linear crystals. One of the output beams show subPoissonian photon statistics, and this allows to use photodetection instead of homodyne detection for diagnostics. (orig.)
Integrated source of broadband quadrature squeezed light
DEFF Research Database (Denmark)
Hoff, Ulrich Busk; Nielsen, Bo Melholt; Andersen, Ulrik Lund
2015-01-01
An integrated silicon nitride resonator is proposed as an ultracompact source of bright single-mode quadrature squeezed light at 850 nm. Optical properties of the device are investigated and tailored through numerical simulations, with particular attention paid to loss associated with interfacing...... the device. An asymmetric double layer stack waveguide geometry with inverse vertical tapers is proposed for efficient and robust fibre-chip coupling, yielding a simulated total loss of -0.75 dB/facet. We assess the feasibility of the device through a full quantum noise analysis and derive the output...
Observation of squeezed states with strong photon-number oscillations
International Nuclear Information System (INIS)
Mehmet, Moritz; Vahlbruch, Henning; Lastzka, Nico; Danzmann, Karsten; Schnabel, Roman
2010-01-01
Squeezed states of light constitute an important nonclassical resource in the field of high-precision measurements, for example, gravitational wave detection, as well as in the field of quantum information, for example, for teleportation, quantum cryptography, and distribution of entanglement in quantum computation networks. Strong squeezing in combination with high purity, high bandwidth, and high spatial mode quality is desirable in order to achieve significantly improved performances contrasting any classical protocols. Here we report on the observation of 11.5 dB of squeezing, together with relatively high state purity corresponding to a vacuum contribution of less than 5%, and a squeezing bandwidth of about 170 MHz. The analysis of our squeezed states reveals a significant production of higher-order pairs of quantum-correlated photons and the existence of strong photon-number oscillations.
Resonance Fluorescence from an Artificial Atom in Squeezed Vacuum
Directory of Open Access Journals (Sweden)
D. M. Toyli
2016-07-01
Full Text Available We present an experimental realization of resonance fluorescence in squeezed vacuum. We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier. We investigate the fluorescence spectra in the weak and strong driving regimes, observing up to 3.1 dB of reduction of the fluorescence linewidth below the ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum on the relative phase of the driving and squeezed vacuum fields. Our results are in excellent agreement with predictions for spectra produced by a two-level atom in squeezed vacuum [Phys. Rev. Lett. 58, 2539 (1987], demonstrating that resonance fluorescence offers a resource-efficient means to characterize squeezing in cryogenic environments.
Nth-powered amplitude squeezing in fan-states
Duc, T M
2002-01-01
Squeezing properties of the Hillery-type N-powered amplitude are investigated in the fan-state vertical bar xi; 2k, f> sub F which is linearly superposed by 2k 2k-quantum nonlinear coherent states in the phase-locked manner. The general expression of squeezing is derived analytically for arbitrary xi, k, N and f showing a multi-directional character of squeezing. For a given k, squeezing may appear to the even power N=2k if f ident to 1 and N>=2k if f not =1 and the number of directions along with the Nth-powered amplitude is squeezed is exactly equal to N, for both f ident to 1 (the light field) and f not =1 (the vibrational motion of the trapped ion). Discussions are also given elucidating the qualitative difference between the cases of f ident to 1 and f not =1.
Magnetorheological Damper Working in Squeeze Mode
Directory of Open Access Journals (Sweden)
Xinglong Gong
2014-05-01
Full Text Available This research is focused on evaluation of the magnetorheological fluids (MRFs based damper which works in squeeze mode. The operation direction of this damper is parallel to the direction of the external magnetic field. Before testing, commercial software ANSYS was used to analyze the magnetic field distribution inside the damper generated by charging current in the coil. The performance of the damper was tested by using the MTS809 (produced by MTS Systems Corporation, USA. For simulation of this damper, a mathematical model was set up. Experimental results showed that the small squeezed MR damper could produce large damping force; for example, the maximum damping force is nearly 6 kN, while the amplitude is 1.2 mm, the frequency is 1.0 Hz, and the current is 2.0 A, and the damping force was controllable by changing the current in the coil. The damping force versus displacement curves are complex. We divide them into four regions for simulation. The maximum damper force increased quickly with the increasing of the current in coil. This kind of damper can be used in vibration isolation for precise equipment.
The mutual attraction of magnetic knots. [solar hydromagnetic instability in sunspot regions
Parker, E. N.
1978-01-01
It is observed that the magnetic knots associated with active regions on the sun have an attraction for each other during the formative period of the active regions, when new magnetic flux is coming to the surface. The attraction disappears when new flux ceases to rise through the surface. Then the magnetic spots and knots tend to come apart, leading to disintegration of the sunspots previously formed. The dissolution of the fields is to be expected, as a consequence of the magnetic repulsion of knots of like polarity and as a consequence of the hydromagnetic exchange instability. The purpose of this paper is to show that the mutual attraction of knots during the formative stages of a sunspot region may be understood as the mutual hydrodynamic attraction of the rising flux tubes. Two rising tubes attract each other, as a consequence of the wake of the leading tube when one is moving behind the other, and as a consequence of the Bernoulli effect when rising side by side.
Oblique propagation of nonlinear hydromagnetic waves: One- and two-dimensional behavior
International Nuclear Information System (INIS)
Malara, F.; Elaoufir, J.
1991-01-01
The one- and two-dimensional behavior of obliquely propagating hydromagnetic waves is analyzed by means of analytical theory and numerical simulations. It is shown that the nonlinear evolution of a one-dimensional MHD wave leads to the formation of a rotational discontinuity and a compressive steepened quasi-linearly polarized pulse whose structure is similar to that of a finite amplitude magnetosonic simple wave. For small propagation angles, the pulse mode (fast or slow) depends on the value of β with respect to unity while for large propagation angles the wave mode is fixed by the sign of the initial density-field correlation. The two-dimensional evolution shows that an MHD wave is unstable against a small-amplitude long-wavelength modulation in the direction transverse to the wave propagation direction. A two-dimensional magnetosonic wave solution is found, in which the density fluctuation is driven by the corresponding total pressure fluctuation, exactly as in the one-dimensional simple wave. Along with the steepening effect, the wave experiences both wave front deformation and a self-focusing effect which may eventually lead to the collapse of the wave. The results compare well with observations of MHD waves in the Earth's foreshock and at comets
Hydromagnetic Rayleigh endash Taylor instability in high-velocity gas-puff implosions
International Nuclear Information System (INIS)
Roderick, N.F.; Peterkin, R.E. Jr.; Hussey, T.W.; Spielman, R.B.; Douglas, M.R.; Deeney, C.
1998-01-01
Experiments using the Saturn pulsed power generator have produced high-velocity z-pinch plasma implosions with velocities over 100 cm/μs using both annular and uniform-fill gas injection initial conditions. Both types of implosion show evidence of the hydromagnetic Rayleigh endash Taylor instability with the uniform-fill plasmas producing a more spatially uniform pinch. Two-dimensional magnetohydrodynamic simulations including unsteady flow of gas from a nozzle into the diode region have been used to investigate these implosions. The instability develops from the nonuniform gas flow field that forms as the gas expands from the injection nozzle. Instability growth is limited to the narrow unstable region of the current sheath. For the annular puff the unstable region breaks through the inner edge of the annulus increasing nonlinear growth as mass ejected from the bubble regions is not replenished by accretion. This higher growth leads to bubble thinning and disruption producing greater nonuniformity at pinch for the annular puff. The uniform puff provides gas to replenish bubble mass loss until just before pinch resulting in less bubble thinning and a more uniform pinch. copyright 1998 American Institute of Physics
Potential flow model for the hydromagnetic Rayleigh--Taylor instability in cylindrical plasmas
International Nuclear Information System (INIS)
Hwang, C.S.; Roderick, N.F.
1987-01-01
A potential flow model has been developed to study the linear behavior of the hydromagnetic equivalent of the Rayleigh--Taylor instability in imploding cylindrical plasmas. Ordinary differential equations are obtained for both (r,z) and (r,θ) disturbances. The model allows the study of the dynamic effects of the moving plasma on the development of the instability. The perturbation equations separate into a geometric part associated with the motion of the interface and a nongeometric part associated with the stability of the interface. In both planes the geometric part shows growth of perturbations for imploding plasmas. The surface is also unstable in both planes for plasmas being imploded by magnetic fields. Analytic solutions are obtained for constant acceleration. These show that the short wavelength perturbations that are most damaging in the (r,z) plane are not affected by the motion of the interface. In the (r,θ) plane the growth of longer wavelength disturbances is affected by the interface motion
On the propagation of hydromagnetic waves in a plasma of thermal and suprathermal components
Kumar, Nagendra; Sikka, Himanshu
2007-12-01
The propagation of MHD waves is studied when two ideal fluids, thermal and suprathermal gases, coupled by magnetic field are moving with the steady flow velocity. The fluids move independently in a direction perpendicular to the magnetic field but gets coupled along the field. Due to the presence of flow in suprathermal and thermal fluids there appears forward and backward waves. All the forward and backward modes propagate in such a way that their rate of change of phase speed with the thermal Mach number is same. It is also found that besides the usual hydromagnetic modes there appears a suprathermal mode which propagates with faster speed. Surface waves are also examined on an interface formed with composite plasma (suprathermal and thermal gases) on one side and the other is a non-magnetized plasma. In this case, the modes obtained are two or three depending on whether the sound velocity in thermal gas is equal to or greater than the sound velocity in suprathermal gas. The results lead to the conclusion that the interaction of thermal and suprathermal components may lead to the occurrence of an additional mode called suprathermal mode whose phase velocity is higher than all the other modes.
A comprehensive field and laboratory study of scale control and scale squeezes in Sumatra, Indonesia
Energy Technology Data Exchange (ETDEWEB)
Oddo, J.E.; Reizer, J.M.; Sitz, C.D. [Champion Technologies, Inc., Houston, TX (United States); Setia, D.E.A. [FMT Production Duri P.T. Caltex Pacific Indonesia (Indonesia); Hinrichsen, C.J. [Texaco Panama, Bellaire, TX (United States); Sujana, W. [P.T. Champion Kumia Djaja Technologies, Jakarta (Indonesia)
1999-11-01
Scale squeezes were performed on thirteen wells in the Duri Field, Sumatra. At the time the squeezes were completed, seven were designed to be `Acid Squeezes` and six were designed to be `Neutral Squeezes.` In the course of preparing for the scale squeezes, produced waters were collected and analyzed. In addition, scale inhibitor evaluations, and inhibitor compatibility studies were completed. Simulated squeezes were done in the laboratory to predict field performance. The methodologies and results of the background work are reported. In addition, the relative effectiveness of the two sets of squeezes is discussed. The inhibitor flowback concentrations alter the squeezes, in all cases, can be explained using speciation chemistry and the amorphous and crystalline phase solubilities of the inhibitor used. The wells squeezed with a more acidic inhibitor have more predictable and uniform inhibitor return concentration curves than the wells squeezed with a more neutral scale inhibitor.
Phenomenology of the squeezed hadronic correlations at RHIC energies
International Nuclear Information System (INIS)
Padula, Sandra S.; Dudek, Danuce M.; Socolowski, Otavio Jr.
2012-01-01
We briefly review the basic theoretical results on bosonic back-to-back correlations (bBBC) and compare our predictions with the first experimental search for squeezed correlations of K + K - pairs, performed by PHENIX. The hadronic squeezed correlations are very sensitive to the functional form of the time emission distribution. The comparison is made for three different kaon time distributions. From such comparison we show that the outcome of the experimental search may still be inconclusive but it does not exclude the existence of squeezing effects on hadrons with in-medium modified masses already at RHIC energies. (author)
Squeezing in an injection-locked semiconductor laser
Inoue, S.; Machida, S.; Yamamoto, Y.; Ohzu, H.
1993-09-01
The intensity-noise properties of an injection-locked semiconductor laser were studied experimentally. The constant-current-driven semiconductor laser producing the amplitude-squeezed state whose intensity noise was reduced below the standard quantum limit (SQL) by 0.72 dB was injection-locked by an external master laser. The measured intensity-noise level of the injection-locked semiconductor laser was 0.91 dB below the SQL. This experimental result indicates that a phase-coherent amplitude-squeezed state or squeezed vacuum state together with a reference local oscillator wave can be generated directly by semiconductor laser systems.
Optimal Operation of a Josephson Parametric Amplifier for Vacuum Squeezing
Malnou, M.; Palken, D. A.; Vale, Leila R.; Hilton, Gene C.; Lehnert, K. W.
2018-04-01
A Josephson parametric amplifier (JPA) can create squeezed states of microwave light, lowering the noise associated with certain quantum measurements. We experimentally study how the JPA's pump influences the phase-sensitive amplification and deamplification of a coherent tone's amplitude when that amplitude is commensurate with vacuum fluctuations. We predict and demonstrate that, by operating the JPA with a single current pump whose power is greater than the value that maximizes gain, the amplifier distortion is reduced and, consequently, squeezing is improved. Optimizing the singly pumped JPA's operation in this fashion, we directly observe 3.87 ±0.03 dB of vacuum squeezing over a bandwidth of 30 MHz.
Squeeze film between porous rough elliptical plates | Deheri ...
African Journals Online (AJOL)
The roughness of the bearing surface is described by a stochastic random variable with non zero mean, variance and skew ness. The associated Reynolds' equation is solved with appropriate boundary conditions. Results for bearing performance characteristics such as load carrying capacity and response time for different ...
Squeezing molecularly thin alkane lubrication films: Layering transistions and wear
DEFF Research Database (Denmark)
Sivebæk, Ion Marius; Samoilov, V. N.; Persson, B. N. J.
2004-01-01
The properties of alkane lubricants confined between two approaching solids are investigated by a model that accounts for the curvature and the elastic properties of the solid surfaces. We consider linear alkane molecules of different chain lengths, C(3)H(8); C(4)H(10); C(8)H(18); C(9)H(20); C(10)H...
Anomalous Quantum Correlations of Squeezed Light
Kühn, B.; Vogel, W.; Mraz, M.; Köhnke, S.; Hage, B.
2017-04-01
Three different noise moments of field strength, intensity, and their correlations are simultaneously measured. For this purpose a homodyne cross-correlation measurement [1] is implemented by superimposing the signal field and a weak local oscillator on an unbalanced beam splitter. The relevant information is obtained via the intensity noise correlation of the output modes. Detection details like quantum efficiencies or uncorrelated dark noise are meaningless for our technique. Yet unknown insight in the quantumness of a squeezed signal field is retrieved from the anomalous moment, correlating field strength with intensity noise. A classical inequality including this moment is violated for almost all signal phases. Precognition on quantum theory is superfluous, as our analysis is solely based on classical physics.
International Nuclear Information System (INIS)
Jha, P.K.
1986-01-01
An attempt has been made to study the problem of free convection hydromagnetic flow of an elastico-viscous fluid past a porous vertical plate in a rotating frame of reference taking ohmic and viscous dissipations into account in the presence of Hall current. The nature of velocity profile shows the existence of multiple boundary layers. Their 'thickness' is seen to decrease with increasing values of Ekman, Hartman and Prandtl numbers and Hall parameter. The graphical study reveals that the increasing values of Hall parameter and Ekman number (for a fixed large value of Hall parameter) exert opposite influence on the flow. (author). 11 refs., 2 tables
EDITORIAL: Squeeze transformation and optics after Einstein
Kim, Young S.; Man'ko, Margarita A.; Planat, Michel
2005-12-01
With this special issue, Journal of Optics B: Quantum and Semiclassical Optics contributes to the celebration of the World Year of Physics held in recognition of five brilliant papers written by Albert Einstein in 1905. There is no need to explain to the readers of this journal the content and importance of these papers, which are cornerstones of modern physics. The 51 contributions in this special issue represent current trends in quantum optics —100 years after the concept of light quanta was introduced. At first glance, in his famous papers of 1905, Einstein treated quite independent subjects—special relativity, the nature and statistical properties of light, electrodynamics of moving bodies and Brownian motion. We now know that all these phenomena are deeply related, and these relations are clearly shown in many papers in this issue. Most of the papers are based on the talks and poster contributions from participants of the 9th International Conference on Squeezed States and Uncertainty Relations (ICSSUR'05), which took place in Besançon, France, 2-6 May, 2005. This was the continuation of a series of meetings, originating with the first workshops organized by Professor Y S Kim at the University of Maryland, College Park, USA, in 1991 and by Professor V I Man'ko at the Lebedev Physical Institute, Moscow in 1992. One of the main topics of ICSSUR'05 and this special issue is the theory and applications of squeezed states and their generalizations. At first glance, one could think that this subject has no relation to Einstein's papers. However, this is not true: the theory of squeezed states is deeply related to special relativity, as far as it is based on the representations of the Lorentz group (see the paper by Kim Y S and Noz M E, S458-S467), which also links the current concepts of entanglement and decoherence with Lorentz-covariance. Besides, studies of the different quantum states of light imply, after all, the study of photon (or photo
Coherent light squeezing states within a modified microring system
Ali, J.; Pornsuwancharoen, N.; Youplao, P.; Aziz, M. S.; Amiri, I. S.; Chaiwong, K.; Chiangga, S.; Singh, G.; Yupapin, P.
2018-06-01
We have proposed the simple method of the squeezed light generation in the modified microring resonator, which is known as the microring conjugate mirror (MCM). When the monochromatic light is input into the MCM, the general form of the squeezed coherent states for a quantum harmonic oscillator can be generated by controlling the additional two side rings, which are the phase modulators. By using the graphical method called the Optiwave program, the coherent squeezed states of coherent light within an MCM can be obtained and interpreted as the amplitude, phase, quadrature and photon number-squeezed states. This method has shown potentials for microring related device design, which can be used before practical applications.
Phonon squeezed states: quantum noise reduction in solids
Hu, Xuedong; Nori, Franco
1999-03-01
This article discusses quantum fluctuation properties of a crystal lattice, and in particular, phonon squeezed states. Squeezed states of phonons allow a reduction in the quantum fluctuations of the atomic displacements to below the zero-point quantum noise level of coherent phonon states. Here we discuss our studies of both continuous-wave and impulsive second-order Raman scattering mechanisms. The later approach was used to experimentally suppress (by one part in a million) fluctuations in phonons. We calculate the expectation values and fluctuations of both the atomic displacement and the lattice amplitude operators, as well as the effects of the phonon squeezed states on macroscopically measurable quantities, such as changes in the dielectric constant. These results are compared with recent experiments. Further information, including preprints and animations, are available in http://www-personal.engin.umich.edu/∼nori/squeezed.html.
Squeezed Phonons: Modulating Quantum Fluctuations of Atomic Displacements.
Hu, Xuedong; Nori, Franco
1997-03-01
We have studied phonon squeezed states and also put forward several proposals for their generation(On phonon parametric process, X. Hu and F. Nori, Phys. Rev. Lett. 76), 2294 (1996); on polariton mechanism, X. Hu and F. Nori, Phys. Rev. B 53, 2419 (1996); on second-order Raman scattering, X. Hu and F. Nori, preprint.. Here, we compare the relative merits and limitations of these approaches, including several factors that will limit the amount of phonon squeezing. In particular, we investigate the effect of the initial thermal states on the phonon modes. Using a model for the phonon density matrix, we also study the mixing of the phonon squeezed states with thermal states, which describes the decay of the phonon coherence. Finally, we calculate the maximum possible squeezing from a phonon parametric process limited by phonon decay.
Price squeezes in electric power: The new Battle of Concord
International Nuclear Information System (INIS)
Kwoka, J.E. Jr.
1992-01-01
The US Court of Appeals opinion in Town of Concord v. Boston Edison offers a vigorous statement of the position that in a regulated market, what may appear to be a price squeeze almost certainly cannot harm the competitive process and therefore should not be held to violate the antitrust laws. While not disputing the possibility of self-serving claims of price squeezes, this article shows that truly anticompetitive price squeezes may indeed occur in the electric power industry and cannot be so readily dismissed. This analysis begins with a brief factual and economic background on price squeezes, then addresses arguments made in Concord and elsewhere seeking to disprove their possibility, and demonstrate that sound economics and good policy require a more balanced approach
Squeezing in multi-mode nonlinear optical state truncation
International Nuclear Information System (INIS)
Said, R.S.; Wahiddin, M.R.B.; Umarov, B.A.
2007-01-01
In this Letter, we show that multi-mode qubit states produced via nonlinear optical state truncation driven by classical external pumpings exhibit squeezing condition. We restrict our discussions to the two- and three-mode cases
Coherent light squeezing states within a modified microring system
Directory of Open Access Journals (Sweden)
J. Ali
2018-06-01
Full Text Available We have proposed the simple method of the squeezed light generation in the modified microring resonator, which is known as the microring conjugate mirror (MCM. When the monochromatic light is input into the MCM, the general form of the squeezed coherent states for a quantum harmonic oscillator can be generated by controlling the additional two side rings, which are the phase modulators. By using the graphical method called the Optiwave program, the coherent squeezed states of coherent light within an MCM can be obtained and interpreted as the amplitude, phase, quadrature and photon number-squeezed states. This method has shown potentials for microring related device design, which can be used before practical applications.
Jovian electron bursts: Correlation with the interplanetary field direction and hydromagnetic waves
International Nuclear Information System (INIS)
Smith, E.J.; Tsurutani, B.T.; Chenette, D.L.; Conlon, T.F.; Simpson, J.A.
1976-01-01
The bursts of relativistic electrons detected on Pioneer 10 upstream from Jupiter and within 400r/subj/ of the planet have been found to be correlated with the interplanetary magnetic field. In the three examples upon which this study is based, during the month prior to the Pioneer 10 encounter, electrons with energies between 3 and 6 MeV escaping from Jupiter's magnetosphere were observed only when the interplanetary magnetic field was along the Jupiter-spacecraft line. In addition, large-amplitude interplanetary waves with characteristic periods of 10 min were observed and found to be well correlated with intervals during which the field was along the Jupiter-spacecraft line. Abrupt changes in the field away from the preferred direction caused equally abrupt terminations of the waves with an accompanying reduction in the electron flux. These results are consistent with propagation of the electrons from Jupiter to Pioneer along, rather than across, the magnetic field lines. The direction of the interplanetary magnetic field is apparently not affected by the electron bursts or by other particles from Jupiter. The average Parker spiral direction is clear with no enhancement in the Jupiter-spacecraft direction. Two alternative possibilities are considered for the origin of the waves. If they were generated near Jupiter, they would have to propagate to the spacecraft in the whistler mode. The expected attenuation of these waves over distances of several hundred r/subj/ an their long travel times make this explanation unattractive. Alternatively, hydromagnetic wave generation by Jovian charged particles, presumably the relativistic electrons themselves, as they travel upstream, appears to be an attractive explanation
Wigner function and tomogram of the excited squeezed vacuum state
International Nuclear Information System (INIS)
Meng Xiangguo; Wang Jisuo; Fan Hongyi
2007-01-01
The excited squeezed light (ESL) can be the outcome of interaction between squeezed light probe and excited atom, which can explore the status and the structure of the atom. We calculate the Wigner function and tomogram of ESL that may be comparable to the experimental measurement of quadrature-amplitude distribution for the light field obtained using balanced homodyne detection. The method of calculation seems new
Wigner function and tomogram of the excited squeezed vacuum state
Energy Technology Data Exchange (ETDEWEB)
Meng Xiangguo [Department of Physics, Liaocheng University, Shandong Province 252059 (China); Wang Jisuo [Department of Physics, Liaocheng University, Shandong Province 252059 (China)]. E-mail: jswang@lcu.edu.cn; Fan Hongyi [Department of Physics, Liaocheng University, Shandong Province 252059 (China); CCAST (World Laboratory), P.O. Box 8730, 100080 Beijing (China)
2007-01-29
The excited squeezed light (ESL) can be the outcome of interaction between squeezed light probe and excited atom, which can explore the status and the structure of the atom. We calculate the Wigner function and tomogram of ESL that may be comparable to the experimental measurement of quadrature-amplitude distribution for the light field obtained using balanced homodyne detection. The method of calculation seems new.
Understanding squeezing of quantum states with the Wigner function
Royer, Antoine
1994-01-01
The Wigner function is argued to be the only natural phase space function evolving classically under quadratic Hamiltonians with time-dependent bilinear part. This is used to understand graphically how certain quadratic time-dependent Hamiltonians induce squeezing of quantum states. The Wigner representation is also used to generalize Ehrenfest's theorem to the quantum uncertainties. This makes it possible to deduce features of the quantum evolution, such as squeezing, from the classical evolution, whatever the Hamiltonian.
Density-dependent squeezing of excitons in highly excited semiconductors
International Nuclear Information System (INIS)
Nguyen Hong Quang.
1995-07-01
The time evolution from coherent states to squeezed states of high density excitons is studied theoretically based on the boson formalism and within the Random Phase Approximation. Both the mutual interaction between excitons and the anharmonic exciton-photon interaction due to phase-space filling of excitons are taken into account. It is shown that the exciton squeezing depends strongly on the exciton density in semiconductors and becomes smaller with increasing the latter. (author). 16 refs, 2 figs
Squeezing of thermal and quantum fluctuations: Universal features
DEFF Research Database (Denmark)
Svensmark, Henrik; Flensberg, Karsten
1993-01-01
We study the classical and quantum fluctuations of a general damped forced oscillator close to a bifurcation instability. Near the instability point, the fluctuations are strongly phase correlated and are squeezed. In the limit of low damping, it is shown that the system has universal features when...... scaled with the damping. The same scaling law applies to the classical and to the quantum regimes. We furthermore show that the coupling to the environment is crucial in the generation of squeezed fluctuations....
Resonance fluorescence from an atom in a squeezed vacuum
Carmichael, H. J.; Lane, A. S.; Walls, D. F.
1987-06-01
The fluorescent spectrum for a two-level atom which is damped by a squeezed vacuum shows striking differences from the spectrum for ordinary resonance fluorescence. For strong coherent driving fields the Mollow triplet depends on the relative phase of the driving field and the squeezed vacuum field. The central peak may have either subnatural linewidth or supernatural linewidth depending on this phase. The mean atomic polarization also shows a phase sensitivity.
Spin squeezing and light entanglement in Coherent Population Trapping
DEFF Research Database (Denmark)
Dantan, Aurelien Romain; Cviklinski, Jean; Giacobino, Elisabeth
2006-01-01
We show that strong squeezing and entanglement can be generated at the output of a cavity containing atoms interacting with two fields in a coherent population trapping situation, on account of a nonlinear Faraday effect experienced by the fields close to a dark-state resonance in a cavity....... Moreover, the cavity provides a feedback mechanism allowing to reduce the quantum fluctuations of the ground state spin, resulting in strong steady state spin squeezing....
Squeezed condensate and confinement in a scalar model
International Nuclear Information System (INIS)
Blaschke, D.; Pavel, H.P.; Roepke, G.; Peradze, G.; Pervushin, V.N.
1996-01-01
The generating functional of a free scalar field theory is generalized to the case of a squeezed vacuum. The squeezed vacuum is prepared by macroscopically populating the original vacuum with pairs of zero energy particles. It is shown that the corresponding quark propagator has no poles on the real-k 2 axis which can be interpreted as quark confinement. In contrast, a scalar meson-like bound state exists as solution of the corresponding Bethe-Salpeter equation. 20 refs
Teleportation of squeezing: Optimization using non-Gaussian resources
Dell'Anno, Fabio; de Siena, Silvio; Adesso, Gerardo; Illuminati, Fabrizio
2010-12-01
We study the continuous-variable quantum teleportation of states, statistical moments of observables, and scale parameters such as squeezing. We investigate the problem both in ideal and imperfect Vaidman-Braunstein-Kimble protocol setups. We show how the teleportation fidelity is maximized and the difference between output and input variances is minimized by using suitably optimized entangled resources. Specifically, we consider the teleportation of coherent squeezed states, exploiting squeezed Bell states as entangled resources. This class of non-Gaussian states, introduced by Illuminati and co-workers [F. Dell’Anno, S. De Siena, L. Albano, and F. Illuminati, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.76.022301 76, 022301 (2007); F. Dell’Anno, S. De Siena, and F. Illuminati, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.81.012333 81, 012333 (2010)], includes photon-added and photon-subtracted squeezed states as special cases. At variance with the case of entangled Gaussian resources, the use of entangled non-Gaussian squeezed Bell resources allows one to choose different optimization procedures that lead to inequivalent results. Performing two independent optimization procedures, one can either maximize the state teleportation fidelity, or minimize the difference between input and output quadrature variances. The two different procedures are compared depending on the degrees of displacement and squeezing of the input states and on the working conditions in ideal and nonideal setups.
Teleportation of squeezing: Optimization using non-Gaussian resources
International Nuclear Information System (INIS)
Dell'Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio; Adesso, Gerardo
2010-01-01
We study the continuous-variable quantum teleportation of states, statistical moments of observables, and scale parameters such as squeezing. We investigate the problem both in ideal and imperfect Vaidman-Braunstein-Kimble protocol setups. We show how the teleportation fidelity is maximized and the difference between output and input variances is minimized by using suitably optimized entangled resources. Specifically, we consider the teleportation of coherent squeezed states, exploiting squeezed Bell states as entangled resources. This class of non-Gaussian states, introduced by Illuminati and co-workers [F. Dell'Anno, S. De Siena, L. Albano, and F. Illuminati, Phys. Rev. A 76, 022301 (2007); F. Dell'Anno, S. De Siena, and F. Illuminati, ibid. 81, 012333 (2010)], includes photon-added and photon-subtracted squeezed states as special cases. At variance with the case of entangled Gaussian resources, the use of entangled non-Gaussian squeezed Bell resources allows one to choose different optimization procedures that lead to inequivalent results. Performing two independent optimization procedures, one can either maximize the state teleportation fidelity, or minimize the difference between input and output quadrature variances. The two different procedures are compared depending on the degrees of displacement and squeezing of the input states and on the working conditions in ideal and nonideal setups.
Fifth International Conference on Squeezed States and Uncertainty Relations
Han, D. (Editor); Janszky, J. (Editor); Kim, Y. S. (Editor); Man'ko, V. I. (Editor)
1998-01-01
The Fifth International Conference on Squeezed States and Uncertainty Relations was held at Balatonfured, Hungary, on 27-31 May 1997. This series was initiated in 1991 at the College Park Campus of the University of Maryland as the Workshop on Squeezed States and Uncertainty Relations. The scientific purpose of this series was to discuss squeezed states of light, but in recent years the scope is becoming broad enough to include studies of uncertainty relations and squeeze transformations in all branches of physics including quantum optics and foundations of quantum mechanics. Quantum optics will continue playing the pivotal role in the future, but the future meetings will include all branches of physics where squeeze transformations are basic. As the meeting attracted more participants and started covering more diversified subjects, the fourth meeting was called an international conference. The Fourth International Conference on Squeezed States and Uncertainty Relations was held in 1995 was hosted by Shanxi University in Taiyuan, China. The fifth meeting of this series, which was held at Balatonfured, Hungary, was also supported by the IUPAP. In 1999, the Sixth International Conference will be hosted by the University of Naples in 1999. The meeting will take place in Ravello near Naples.
Energy Technology Data Exchange (ETDEWEB)
Begnazarov, T.
1979-01-01
The remaining petroleum in the flooded zone is determined by the ratio of viscosity forces to the forces of the surface tension, which are expressed by the coefficient Ka. With this, for each kind of porous medium, there exists a natural cricial value Ka. For the purpose of studying the effect of the given parameters on the value of the remaining petroleum, experiments were carried out on artificial specimens. In the tests, using petroleum of the Mishkin deposit, the surface tension on the boundary of the petroleum with the distilled water and alkaline solutions were respectively equal to 37.1 and 1.33 dynes per centimeter. The experiments showed, that the squeezing out of the petroleum with water or alkaline solutions leads to similar results. This means, that the composite parameter Ka does not affect the value of the remaining petroleum saturation. The effectiveness of the final squeezing out of the petroleum of increased viscosity was also studied. These experiments were carried out in two variations of the injection of the squeezed out agent: in the first variation, the petroleum was squeezed out with water in the first stage, and in the second stage it was squeezed out by an alkaline solution, and in the subsequent stages, a change in the squeezing out agent took place. By finishing the first stage, the attained values of the coefficients of the squeezing out were practically similar (0.72). In the second stage, the final squeezing out of the petroleum with a solution of alkaline, provided a major effect.
Squeezed noise in precision force measurements
International Nuclear Information System (INIS)
Bocko, M.F.; Bordoni, F.; Fuligni, F.; Johnson, W.W.
1986-01-01
The effort to build gravitational radiation antennae with sensitivity sufficient to detect bursts of radiation from supernovae in the Virgo cluster of galaxies has caused a consideration of the fundamental limits for the detection of weak forces. The existing Weber bar detectors will be eventually limited, by the phase insensitive transducers now used, to noise temperatures no better than that of the first amplifier which follows the transducer. Even for a quantum limited amplifier this may not give the sensitivity required to definitively detect gravitational radiation. In a 'back action evasion' measurement a specific phase sensitive transducer would be used. It is believed that by the technique of measuring one of the two antenna phases it is possible to reach an effective noise temperature for the measured phase which is far below the amplifier noise temperature. This is at the expense of an infinite noise temperature in the unmeasured antenna phase and is thus described as squeezing the noise. The authors outline the theoretical model for the behavior of such systems and present data from several experiments which demonstrate the main features of a back action evasion measurement. (Auth.)
EDITORIAL: Squeezed states and uncertainty relations
Jauregue-Renaud, Rocio; Kim, Young S.; Man'ko, Margarita A.; Moya-Cessa, Hector
2004-06-01
This special issue of Journal of Optics B: Quantum and Semiclassical Optics is composed mainly of extended versions of talks and papers presented at the Eighth International Conference on Squeezed States and Uncertainty Relations held in Puebla, Mexico on 9-13 June 2003. The Conference was hosted by Instituto de Astrofísica, Óptica y Electrónica, and the Universidad Nacional Autónoma de México. This series of meetings began at the University of Maryland, College Park, USA, in March 1991. The second and third workshops were organized by the Lebedev Physical Institute in Moscow, Russia, in 1992 and by the University of Maryland Baltimore County, USA, in 1993, respectively. Afterwards, it was decided that the workshop series should be held every two years. Thus the fourth meeting took place at the University of Shanxi in China and was supported by the International Union of Pure and Applied Physics (IUPAP). The next three meetings in 1997, 1999 and 2001 were held in Lake Balatonfüred, Hungary, in Naples, Italy, and in Boston, USA, respectively. All of them were sponsored by IUPAP. The ninth workshop will take place in Besançon, France, in 2005. The conference has now become one of the major international meetings on quantum optics and the foundations of quantum mechanics, where most of the active research groups throughout the world present their new results. Accordingly this conference has been able to align itself to the current trend in quantum optics and quantum mechanics. The Puebla meeting covered most extensively the following areas: quantum measurements, quantum computing and information theory, trapped atoms and degenerate gases, and the generation and characterization of quantum states of light. The meeting also covered squeeze-like transformations in areas other than quantum optics, such as atomic physics, nuclear physics, statistical physics and relativity, as well as optical devices. There were many new participants at this meeting, particularly
Predicting Tunnel Squeezing Using Multiclass Support Vector Machines
Directory of Open Access Journals (Sweden)
Yang Sun
2018-01-01
Full Text Available Tunnel squeezing is one of the major geological disasters that often occur during the construction of tunnels in weak rock masses subjected to high in situ stresses. It could cause shield jamming, budget overruns, and construction delays and could even lead to tunnel instability and casualties. Therefore, accurate prediction or identification of tunnel squeezing is extremely important in the design and construction of tunnels. This study presents a modified application of a multiclass support vector machine (SVM to predict tunnel squeezing based on four parameters, that is, diameter (D, buried depth (H, support stiffness (K, and rock tunneling quality index (Q. We compiled a database from the literature, including 117 case histories obtained from different countries such as India, Nepal, and Bhutan, to train the multiclass SVM model. The proposed model was validated using 8-fold cross validation, and the average error percentage was approximately 11.87%. Compared with existing approaches, the proposed multiclass SVM model yields a better performance in predictive accuracy. More importantly, one could estimate the severity of potential squeezing problems based on the predicted squeezing categories/classes.
Squeeze strengthening of magnetorheological fluids using mixed mode operation
Becnel, A. C.; Sherman, S. G.; Hu, W.; Wereley, N. M.
2015-05-01
This research details a novel method of increasing the shear yield stress of magnetorheological fluids by combining shear and squeeze modes of operation to manipulate particle chain structures, so-called squeeze strengthening. Using a custom built Searle cell magnetorheometer, which is a model device emulating a rotary magnetorheological energy absorber (MREA), the contribution of squeeze strengthening to the total controllable yield force is experimentally investigated. Using an eccentric rotating inner cylinder, characterization data from large (1 mm) and small (0.25 mm) nominal gap geometries are compared to investigate the squeeze strengthening effect. Details of the experimental setup and method are presented, and a hybrid model is used to explain experimental trends. This study demonstrates that it is feasible, utilizing squeeze strengthening to increase yield stress, to either (1) design a rotary MREA of a given volume to achieve higher energy absorption density (energy absorbed normalized by active fluid volume), or (2) reduce the volume of a given rotary MREA to achieve the same energy absorption density.
Quantum Phonon Optics: Squeezing Quantum Noise in the Atomic Displacements.
Hu, X.; Nori, F.
1996-03-01
We have investigated(X. Hu and F. Nori, Physical Review B, in press; preprints.) coherent and squeezed quantum states of phonons. Squeezed states are interesting because they allow the possibility of modulating the quantum fluctuations of atomic displacements below the zero-point quantum noise level of phonon vacuum states. We have studiedfootnotemark[1] the possibility of squeezing quantum noise in the atomic displacement using a polariton-based approach and also a method based on the three-phonon anharmonic interaction. Our focus here is on the first approach. We have diagonalized the polariton Hamiltonian and calculated the corresponding expectation values and fluctuations of both the atomic displacement and the lattice amplitude operators (the later is the phonon analog of the electric field operator for photons). Our results shows that squeezing of quantum fluctuations in the atomic displacements can be achieved with appropriate initial states of both photon and phonon fields. The degree of squeezing is directly related to the crystal susceptibility, which is indicative of the interaction strength between the incident light and the crystal.
Fourth International Conference on Squeezed States and Uncertainty Relations
Han, D. (Editor); Peng, Kunchi (Editor); Kim, Y. S. (Editor); Manko, V. I. (Editor)
1996-01-01
The fourth International Conference on Squeezed States and Uncertainty Relations was held at Shanxi University, Taiyuan, Shanxi, China, on June 5 - 9, 1995. This conference was jointly organized by Shanxi University, the University of Maryland (U.S.A.), and the Lebedev Physical Institute (Russia). The first meeting of this series was called the Workshop on Squeezed States and Uncertainty Relations, and was held in 1991 at College Park, Maryland. The second and third meetings in this series were hosted in 1992 by the Lebedev Institute in Moscow, and in 1993 by the University of Maryland Baltimore County, respectively. The scientific purpose of this series was initially to discuss squeezed states of light, but in recent years, the scope is becoming broad enough to include studies of uncertainty relations and squeeze transformations in all branches of physics, including, of course, quantum optics and foundations of quantum mechanics. Quantum optics will continue playing the pivotal role in the future, but the future meetings will include all branches of physics where squeeze transformations are basic transformation. This transition took place at the fourth meeting of this series held at Shanxi University in 1995. The fifth meeting in this series will be held in Budapest (Hungary) in 1997, and the principal organizer will be Jozsef Janszky of the Laboratory of Crystal Physics, P.O. Box 132, H-1052. Budapest, Hungary.
Entropy Squeezing in Coupled Field-Superconducting Charge Qubit with Intrinsic Decoherence
Institute of Scientific and Technical Information of China (English)
YAN Xue-Qun; SHAO Bin; ZOU Jian
2007-01-01
We investigate the entropy squeezing in the system of a superconducting charge qubit coupled to a single mode field. We find an exact solution of the Milburn equation for the system and discuss the influence of intrinsic decoherence on entropy squeezing. As a comparison, we also consider the variance squeezing. Our results show that in the absence of the intrinsic decoherence both entropy and variance squeezings have the same periodic properties of time,and occur at the same range of time. However, when the intrinsic decoherence is considered, we find that as the time going on the entropy squeezing disappears fast than the variance squeezing, there exists a range of time where entropy squeezing can occur but variance squeezing cannot.
Quantum entanglement and nonlocality properties of two-mode Gaussian squeezed states
International Nuclear Information System (INIS)
Shao-Hua, Xiang; Bin, Shao; Ke-Hui, Song
2009-01-01
Quantum entanglement and nonlocality properties of a family of two-mode Gaussian pure states have been investigated. The results show that the entanglement of these states is determined by both the two-mode squeezing parameter and the difference of the two single-mode squeezing parameters. For the same two-mode squeezing parameter, these states show larger entanglement than the usual two-mode squeezed vacuum state. The violation of Bell inequality depends strongly on all the squeezing parameters of these states and disappears completely in the limit of large squeezing. In particular, these states can exhibit much stronger violation of local realism than two-mode squeezed vacuum state in the range of experimentally available squeezing values. (general)
International Nuclear Information System (INIS)
Roderick, N.F.; Cochrane, K.; Douglas, M.R.
1998-01-01
Previous investigations carried out to study various methods of seeding the hydromagnetic Rayleigh-Taylor instability in magnetohydrodynamic simulations showed features similar to those seen in hydrodynamic calculations. For periodic single-mode initiations the results showed the appearance of harmonics as the single modes became nonlinear. For periodic multi-mode initiations new modes developed that indicated the presence of mode coupling. The MHD simulations used parameters of the high velocity large radius z-pinch experiments performed in the Z-accelerator at Sandia National Laboratories. The cylindrical convergent geometry and variable acceleration of these configurations made comparison with analytic, developed for planar geometry with constant acceleration, difficult. A set of calculations in planar geometry using constant current to produce acceleration and parameters characteristic of the cylindrical implosions has been performed to allow a better comparison. Results of these calculations, comparison with analytic theory, and comparison with the cylindrical configuration calculations will be discussed
Directory of Open Access Journals (Sweden)
Marco Rosales-Vera
2012-01-01
Full Text Available The problem of a hydromagnetic hot two-dimensional laminar jet issuing vertically into an otherwise quiescent fluid of a lower temperature is studied. We propose solutions to the boundary layer equations using the classical Fourier series. The method is essentiall to transform the boundary layer equations to a coupled set of nonlinear first-order ordinary differential equations through the Fourier series. The accuracy of the results has been tested by the comparison of the velocity distributions obtained by the Fourier series with those calculated by finite difference method. The results show that the present method, based on the Fourier series, is an efficient method, suitable to solve boundary layer equations applied to plane jet flows with high accuracy.
International Nuclear Information System (INIS)
Minami, Kazuo; Sato, Kazunori.
1978-09-01
The dynamic shear stabilization of the hydromagnetic instability in low-beta plasmas by an axial RF current whose frequency is not much smaller than the ion cyclotron frequency ωsub(ci) is analyzed in some detail. We adopt the simple model of a uniform plasma column with infinite conductivity. Attention is limited to the case of the m = 1 kink mode with long wave lengths. The Mathieu equation, in which the effect of the ion cyclotron motion is taken into account, is derived. It is shown that the dynamic shear stabilization is still effective, even if the frequency of the applied RF current is of the order of ωsub(ci), which is considerably higher than the frequencies believed to be available in the previous analyses. (author)
Directory of Open Access Journals (Sweden)
A.S. Eegunjobi
Full Text Available Numerical analysis of the intrinsic irreversibility of a mixed convection hydromagnetic flow of an electrically conducting couple stress fluid through upright channel filled with a saturated porous medium and radiative heat transfer was carried out. The thermodynamics first and second laws were employed to examine the problem. We obtained the dimensionless nonlinear differential equations and solves numerically with shooting procedure joined with a fourth order Runge-Kutta-Fehlberg integration scheme. The temperature and velocity obtained, used to analyse the entropy generation rate together with some various physical parameters of the flow. Our results are presented graphically and talk over. Keywords: MHD channel flow, Couple stress fluid, Porous medium, Thermal radiation, Entropy generation, Injection/suction
Slowing Quantum Decoherence by Squeezing in Phase Space
Le Jeannic, H.; Cavaillès, A.; Huang, K.; Filip, R.; Laurat, J.
2018-02-01
Non-Gaussian states, and specifically the paradigmatic cat state, are well known to be very sensitive to losses. When propagating through damping channels, these states quickly lose their nonclassical features and the associated negative oscillations of their Wigner function. However, by squeezing the superposition states, the decoherence process can be qualitatively changed and substantially slowed down. Here, as a first example, we experimentally observe the reduced decoherence of squeezed optical coherent-state superpositions through a lossy channel. To quantify the robustness of states, we introduce a combination of a decaying value and a rate of decay of the Wigner function negativity. This work, which uses squeezing as an ancillary Gaussian resource, opens new possibilities to protect and manipulate quantum superpositions in phase space.
Slip analysis of squeezing flow using doubly stratified fluid
Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha
2018-06-01
The non-isothermal flow is modeled and explored for squeezed fluid. The influence of velocity, thermal and solutal slip effects on transport features of squeezed fluid are analyzed through Darcy porous channel when fluid is moving due to squeezing of upper plate towards the stretchable lower plate. Dual stratification effects are illustrated in transport equations. A similarity analysis is performed and reduced governing flow equations are solved using moderated and an efficient convergent approach i.e. Homotopic technique. The significant effects of physical emerging parameters on flow velocity, temperature and fluid concentration are reporting through various plots. Graphical explanations for drag force, Nusselt and Sherwood numbers are stated and examined. The results reveal that minimum velocity field occurs near the plate, whereas it increases far away from the plate for strong velocity slip parameter. Furthermore, temperature and fluid concentration significantly decreases with increased slip effects. The current analysis is applicable in some advanced technological processes and industrial fluid mechanics.
Pump-dump iterative squeezing of vibrational wave packets.
Chang, Bo Y; Sola, Ignacio R
2005-12-22
The free motion of a nonstationary vibrational wave packet in an electronic potential is a source of interesting quantum properties. In this work we propose an iterative scheme that allows continuous stretching and squeezing of a wave packet in the ground or in an excited electronic state, by switching the wave function between both potentials with pi pulses at certain times. Using a simple model of displaced harmonic oscillators and delta pulses, we derive the analytical solution and the conditions for its possible implementation and optimization in different molecules and electronic states. We show that the main constraining parameter is the pulse bandwidth. Although in principle the degree of squeezing (or stretching) is not bounded, the physical resources increase quadratically with the number of iterations, while the achieved squeezing only increases linearly.
Novel polymeric phosphonate scale inhibitors for improved squeeze treatment lifetimes
Energy Technology Data Exchange (ETDEWEB)
Jackson, G.E.; Poynton, N.; McLaughlin, K.; Clark, D.R.
1996-12-31
New patented chemistry has provided an exciting discovery which may be used to reduce costs in scale squeeze applications. Phosphomethylated polyamines (PMPAs) have been found to possess outstanding adsorption-desorption properties which generate long squeeze lifetimes. This paper describes the core-flood tests and modelling work, which highlight these properties, plus additional scale inhibition performance studies to demonstrate the all-round capabilities of this chemistry for squeeze treatments. An example of a PMPA is used to show the extremely viable adsorption and desorption isotherms. These illustrate the efficient way in which the desorption occurs to minimise the chemical in the returns with a benefit of reduced chemical content in the discharge. The PMPA also demonstrates that both polymer and phosphonate properties can be embraced in a single product (e.g. dual scale control mechanisms) confirming that this chemistry is a true polymeric phosphonate. 13 refs., 12 figs., 1 tab.
Optical bistability of a thin film of resonant atoms in a phase-sensitive thermostate
International Nuclear Information System (INIS)
Basharov, A.M.
1995-01-01
It is shown theoretically that when a thin film of two-level atoms interacting with a resonant coherent electromagnetic wave is additionally illuminated with a squeezed field, a bistable transmission/reflection regime for coherent waves is obtained. This regime depends strongly on the phase difference between the coherent and the squeezed fields. New regimes, including a bistable regime, for the interaction of a coherent field with a film of resonant atoms are predicted based on this phenomenon. 14 refs., 5 figs
Waveguide Cavity Resonator as a Source of Optical Squeezing
Stefszky, M.; Ricken, R.; Eigner, C.; Quiring, V.; Herrmann, H.; Silberhorn, C.
2017-04-01
We present the generation of continuous-wave optical squeezing from a titanium-in-diffused lithium niobate waveguide resonator. We directly measure 2.9 ±0.1 dB of single-mode squeezing, which equates to a produced level of 4.9 ±0.1 dB after accounting for detection losses. This device showcases the current capabilities of this waveguide architecture and precipitates more complicated integrated continuous-wave quantum devices in the continuous-variable regime.
Improvement of an Atomic Clock using Squeezed Vacuum
DEFF Research Database (Denmark)
Kruse, I.; Lange, K; Peise, Jan
2016-01-01
, the vacuum noise restricts the precision of the interferometer to the standard quantum limit (SQL). Here, we propose and experimentally demonstrate a novel clock configuration that surpasses the SQL by squeezing the vacuum in the empty input state. We create a squeezed vacuum state containing an average of 0.......75 atoms to improve the clock sensitivity of 10000 atoms by 2.05+0.34−0.37 dB. The SQL poses a significant limitation for today’s microwave fountain clocks, which serve as the main time reference. We evaluate the major technical limitations and challenges for devising a next generation of fountain clocks...
Low frequency phase signal measurement with high frequency squeezing
Zhai, Zehui; Gao, Jiangrui
2011-01-01
We calculate the utility of high-frequency squeezed-state enhanced two-frequency interferometry for low-frequency phase measurement. To use the high-frequency sidebands of the squeezed light, a two-frequency intense laser is used in the interferometry instead of a single-frequency laser as usual. We find that the readout signal can be contaminated by the high-frequency phase vibration, but this is easy to check and avoid. A proof-of-principle experiment is in the reach of modern quantum optic...
Squeezing a wave packet with an angular-dependent mass
Energy Technology Data Exchange (ETDEWEB)
Schmidt, Alexandre G M [Departamento de Ciencias Exatas, Universidade Federal Fluminense, Av. dos Trabalhadores 420, Volta Redonda RJ, CEP 27255-125 (Brazil)], E-mail: agmschmidt@gmail.com, E-mail: agmschmidt@pq.cnpq.br
2009-06-19
We present a new effect of position-dependent mass (PDM) systems: the possibility of creating squeezed wave packets at the partial revival times. We solve exactly the PDM Schroedinger equation for the two-dimensional quantum rotor with two effective masses {mu}({theta}), both free and interacting with a uniform electric field, and present their energy eigenvalues and eigenfunctions in terms of Mathieu functions. For the first one, in order to squeeze the wave packet it is necessary to apply an electric field; for the second one such an effect can be achieved without the field.
Squeezing a wave packet with an angular-dependent mass
International Nuclear Information System (INIS)
Schmidt, Alexandre G M
2009-01-01
We present a new effect of position-dependent mass (PDM) systems: the possibility of creating squeezed wave packets at the partial revival times. We solve exactly the PDM Schroedinger equation for the two-dimensional quantum rotor with two effective masses μ(θ), both free and interacting with a uniform electric field, and present their energy eigenvalues and eigenfunctions in terms of Mathieu functions. For the first one, in order to squeeze the wave packet it is necessary to apply an electric field; for the second one such an effect can be achieved without the field
Displacement of microwave squeezed states with Josephson parametric amplifiers
Energy Technology Data Exchange (ETDEWEB)
Zhong, Ling; Baust, Alexander; Xie, Edwar; Schwarz, Manuel; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Fedorov, Kirill; Menzel, Edwin; Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Betzenbichler, Martin; Pogorzalek, Stefan; Haeberlein, Max; Eder, Peter; Goetz, Jan; Wulschner, Karl Friedrich; Huebl, Hans; Deppe, Frank [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany)
2015-07-01
Propagating quantum microwaves are promising building blocks for quantum communication. Interestingly, such itinerant quantum microwaves can be generated in the form of squeezed photon states by Josephson parametric amplifiers (JPA). We employ a specific ''dual-path'' setup for both state reconstruction and JPA characterization. Displacement operations are performed by using a directional coupler after the squeezing. We compare our results with theory predictions. In particular, we discuss our experiments in the context of remote state preparation and quantum teleportation with propagating microwaves.
The Wigner distribution function for squeezed vacuum superposed state
International Nuclear Information System (INIS)
Zayed, E.M.E.; Daoud, A.S.; AL-Laithy, M.A.; Naseem, E.N.
2005-01-01
In this paper, we construct the Wigner distribution function for a single-mode squeezed vacuum mixed-state which is a superposition of the squeezed vacuum state. This state is defined as a P-representation for the density operator. The obtained Wigner function depends, beside the phase-space variables, on the mean number of photons occupied by the coherent state of the mode. This mean number relates to the mean free path through a given relation, which enables us to measure this number experimentally by measuring the mean free path
Engineering squeezed states of microwave radiation with circuit quantum electrodynamics
International Nuclear Information System (INIS)
Li Pengbo; Li Fuli
2011-01-01
We introduce a squeezed state source for microwave radiation with tunable parameters in circuit quantum electrodynamics. We show that when a superconducting artificial multilevel atom interacting with a transmission line resonator is suitably driven by external classical fields, two-mode squeezed states of the cavity modes can be engineered in a controllable fashion from the vacuum state via adiabatic following of the ground state of the system. This scheme appears to be robust against decoherence and is realizable with present techniques in circuit quantum electrodynamics.
A faster urethral pressure reflectometry technique for evaluating the squeezing function
DEFF Research Database (Denmark)
Klarskov, Niels; Saaby, Marie-Louise; Lose, Gunnar
2013-01-01
Abstract Objective. Urethral pressure reflectometry (UPR) has shown to be superior in evaluating the squeeze function compared to urethral pressure profilometry. The conventional UPR measurement (step method) required up to 15 squeezes to provide one measure of the squeezing opening pressure...
Super-Poissonian Shot Noise of Squeezed-Magnon Mediated Spin Transport.
Kamra, Akashdeep; Belzig, Wolfgang
2016-04-08
The magnetization of a ferromagnet (F) driven out of equilibrium injects pure spin current into an adjacent conductor (N). Such F|N bilayers have become basic building blocks in a wide variety of spin-based devices. We evaluate the shot noise of the spin current traversing the F|N interface when F is subjected to a coherent microwave drive. We find that the noise spectrum is frequency independent up to the drive frequency, and increases linearly with frequency thereafter. The low frequency noise indicates super-Poissonian spin transfer, which results from quasiparticles with effective spin ℏ^{*}=ℏ(1+δ). For typical ferromagnetic thin films, δ∼1 is related to the dipolar interaction-mediated squeezing of F eigenmodes.
International Nuclear Information System (INIS)
Chuan-Mei, Xie; Shao-Long, Wan; Hong-Yi, Fan
2010-01-01
Based on the displacement-squeezing related squeezed coherent state representation |z) g and using the technique of integration within an ordered product of operators, this paper finds a generalized Fresnel operator, whose matrix element in the coordinate representation leads to a generalized Collins formula (Huygens–Fresnel integration transformation describing optical diffraction). The generalized Fresnel operator is derived by a quantum mechanical mapping from z to sz - rz * in the |z) g representation, while |z) g in phase space is graphically denoted by an ellipse. (classical areas of phenomenology)
Czech Academy of Sciences Publication Activity Database
Šimkanin, Ján; Brestenský, J.; Ševčík, S.
2006-01-01
Roč. 50, č. 4 (2006), s. 645-661 ISSN 0039-3169 R&D Projects: GA ČR GP205/04/P182 Grant - others:VEGA(SK) 1/0212/03 Institutional research plan: CEZ:AV0Z30120515 Keywords : non-uniform stratification of the Earth's core * linear magnetoconvection * diffusive hydromagnetic instabilities Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.603, year: 2006
Probe transparency in a two-level medium embedded by a squeezed vacuum
International Nuclear Information System (INIS)
Swain, S.; Zhou, P.
1994-08-01
Effect of the detuning on the probe absorption spectra of a two-level system with and without a classically driven field in a squeezed vacuum is investigated. For a strong squeezing, there is a threshold which determines the positions and widths of the absorption peaks, for the squeezed parameter M. In a large detuning, the spectra exhibit some resemblance to the Fano spectrum. The squeezing-induced transparency occurs at the frequency 2ω L - ω A in the minimum-uncertainty squeezed vacuum. This effect is not phase-sensitive. (author). 15 refs, 8 figs
Squeezing and entangling nuclear spins in helium 3
DEFF Research Database (Denmark)
Reinaudi, Gael; Sinatra, Alice; Dantan, Aurelien Romain
2007-01-01
We present a realistic model for transferring the squeezing or the entanglement of optical field modes to the collective ground state nuclear spin of 3He using metastability exchange collisions. We discuss in detail the requirements for obtaining good quantum state transfer efficiency and study t...
Light squeezing in optical parametric amplification beyond the ...
Indian Academy of Sciences (India)
of the medium the squeezing effect is increased, the same property we have obtained in our present study. ... classical case [2,9], the introduction of the idler mode from the rare side of the medium, a2(0), is necessary to ... ever, in contrast with the coherent state, the combination mode has unequal uncertainty. 0. 0.02. 0.04.
Quantum reconstruction of an intense polarization squeezed optical state
DEFF Research Database (Denmark)
Marquardt, Ch.; Heersink, J.; Dong, R.
2007-01-01
We perform a reconstruction of the polarization sector of the density matrix of an intense polarization squeezed beam starting from a complete set of Stokes measurements. By using an appropriate quasidistribution, we map this onto the Poincare space, providing a full quantum mechanical characteri...
Squeezed states from a quantum deformed oscillator Hamiltonian
Energy Technology Data Exchange (ETDEWEB)
Ramírez, R. [IFLP, CONICET–Department of Mathematics, University of La Plata c.c. 67 1900, La Plata (Argentina); Reboiro, M., E-mail: marta.reboiro@gmail.com [IFLP, CONICET–Department of Physics, University of La Plata c.c. 67 1900, La Plata (Argentina)
2016-03-11
The spectrum and the time evolution of a system, which is modeled by a non-hermitian quantum deformed oscillator Hamiltonian, is analyzed. The proposed Hamiltonian is constructed from a non-standard realization of the algebra of Heisenberg. We show that, for certain values of the coupling constants and for a range of values of the deformation parameter, the deformed Hamiltonian is a pseudo-hermitic Hamiltonian. We explore the conditions under which the Hamiltonian is similar to a Swanson Hamiltonian. Also, we show that the lowest eigenstate of the system is a squeezed state. We study the time evolution of the system, for different initial states, by computing the corresponding Wigner functions. - Highlights: • A generalization of the squeezed harmonic oscillator is constructed from a non-standard realization of the Heisenberg algebra. • It is proved that, for certain values of the parameters of the model, the Hamiltonian is a pseudo-hermitian Hamiltonian. • It is shown that the lowest eigenstate of the Hamiltonian is a squeezed state. • The squeezing behavior of the associated Gazeau–Klauder state, as a function of time, is discussed.
Scoping study on coastal squeeze in the Ayeyarwady Delta
Kroon, M.E.N.; Rutten, M.M.; Stive, M.J.F.; Wunna, S.
2015-01-01
Coastal squeeze is the reduction in the space of coastal habitats to operate (Phan et al, 2014) and an important cause for coastline retreat, increase in flood risk, salinity intrusion etc. Land use changes, such as deforestation and urbanization, reduce the space of natural habitats, such as
US nuclear industry plans squeeze on O and M costs
International Nuclear Information System (INIS)
Anon.
1994-01-01
The United States nuclear industry, still the largest in the world with 107 operating commercial plants, wants to squeeze still more fat out of operation and maintenance costs. Success or failure could decide whether many operating units remain competitive with other forms of baseload electricity generation over the coming decade. (Author)
Estimating the distribution of salt cavern squeeze using subsidence measurements
Fokker, P.A.; Visser, J.
2014-01-01
We report a field study on solution mining of magnesium chloride from bischofite layers in the Netherlands at depths between 1500 and 1850 m. Subsidence that was observed in the area is due to part of the brine production being realized by cavern squeeze; some of which were connccted. Wc used an
Polarization squeezing and entanglement produced by a frequency doubler
DEFF Research Database (Denmark)
Andersen, Ulrik Lund; Buchhave, Preben
2003-01-01
The quantum mechanical polarization properties of a nondegenerate second harmonic generator, where a nonlinear type II crystal is placed inside a cavity, are investigated theoretically. We demonstrate the possibility of strong squeezing of the continuous Stokes parameters as well as strong...... entanglement between them....
Geometric phases for nonlinear coherent and squeezed states
International Nuclear Information System (INIS)
Yang Dabao; Chen Ying; Chen Jingling; Zhang Fulin
2011-01-01
The geometric phases for standard coherent states which are widely used in quantum optics have attracted considerable attention. Nevertheless, few physicists consider the counterparts of nonlinear coherent states, which are useful in the description of the motion of a trapped ion. In this paper, the non-unitary and non-cyclic geometric phases for two nonlinear coherent and one squeezed states are formulated, respectively. Moreover, some of their common properties are discussed, such as gauge invariance, non-locality and nonlinear effects. The nonlinear functions have dramatic impacts on the evolution of the corresponding geometric phases. They speed the evolution up or down. So this property may have an application in controlling or measuring geometric phase. For the squeezed case, when the squeezed parameter r → ∞, the limiting value of the geometric phase is also determined by a nonlinear function at a given time and angular velocity. In addition, the geometric phases for standard coherent and squeezed states are obtained under a particular condition. When the time evolution undergoes a period, their corresponding cyclic geometric phases are achieved as well. And the distinction between the geometric phases of the two coherent states may be regarded as a geometric criterion.
Squeezing effects of an atom laser: Beyond the linear model
International Nuclear Information System (INIS)
Jing Hui; Ge Molin; Chen Jingling
2002-01-01
We investigate the quantum dynamics and statistics of an atom laser by taking into account binary atom-atom collisions. The rotating wave approximation Hamiltonian of the system is solved analytically . We show that the nonlinear atom-atom interactions could yield periodic quadrature squeezing effects in the atom laser output beam, although the input radio frequency field is in a Glauber coherent state
Light squeezing in optical parametric ampliﬁcation beyond the ...
Indian Academy of Sciences (India)
The variances have different signs for a range of values of and their variations are in opposite directions. We also show that this property is strongly dependent on the relative refractive index of the medium (). It is worth mentioning that the relative index dependency is not an explicit feature in squeezing of OPA under ...
Why the Marriage Squeeze Cannot Cause Dowry Inflation
Anderson, K.S.
2000-01-01
It has been argued that rising dowry payments are caused by population growth.According to that explanation, termed the `marriage squeeze', a population increase leads to an excess supply of brides since men marry younger women.As a result, dowry payments rise in order to clear the marriage
Institute of Scientific and Technical Information of China (English)
李春先; 方卯发
2003-01-01
We study the squeezing for a two-level atom in the Jaynes-Cummings model with intensity-dependent coupling using quantum information entropy, and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing. Our results show that, the squeezed component number depends on the atomic initial distribution angle, while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing. Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.
Institute of Scientific and Technical Information of China (English)
李春先; 方卯发; 等
2003-01-01
We study the squeezing for a two-level atom in the Jaynes-Cumings model with intensity-dependent coupling using quantum information entropy,and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing.Our results show that,the squeezed component number depends on the atomic initial distribution angle,while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing.Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.
International Nuclear Information System (INIS)
Giri, Dilip Kumar; Gupta, P S
2003-01-01
The concept of fourth-order squeezing of the electromagnetic field is investigated in the fundamental mode in spontaneous and stimulated four- and six-wave mixing processes under the short-time approximation based on a fully quantum mechanical approach. The coupled Heisenberg equations of motion involving real and imaginary parts of the quadrature operators are established. The possibility of obtaining fourth-order squeezing is studied. The dependence of fourth-order squeezing on the number of photons is also investigated. It is shown that fourth-order squeezing, which is a higher-order squeezing, allows a much larger fractional noise reduction than lower-order squeezing. It is shown that squeezing is greater in a stimulated process than the corresponding squeezing in spontaneous interaction. The conditions for obtaining maximum and minimum squeezing are obtained. We have also established the non-classical nature of squeezed radiation using the Glauber-Sudarshan representation
Coherent interference effects and squeezed light generation in optomechanical systems
Qu, Kenan
My Ph.D. dissertation is on the fundamental effects in optomechanical systems (OMS) and their important applications. The OMS are based on the possibility of the mechanical motion produced by few photons incident on the mechanical device. This dissertation presents several applications of the OMS in the area of storage of light in long-lived phonons, single mode optomechanical Ramsey interferometry, and generation of large amount of squeezing in the output radiation. The long-lived phonons can be monitored and controlled via optical means as was experimentally demonstrated. To show this, I develop the theory of transient electromagnetically induced transparency (EIT). For further applications like state transfer, especially over very different frequency regimes, I consider double-cavity OMS, where the two cavities can correspond to different spectral domains, yet the state transfer is possible via phonons. The state transfer is based on a new effect, electromagnetically induced absorption (EIA), where one uses a second control field from the other cavity to produce an absorption peak inside the EIT window. All these involve the interference of various path ways via which a final state is reached. The following chapter shows how Fano-like interference can arise in OMS. A Fano asymmetry parameter for OMS was defined. The last two chapters deal with the question if OMS can be efficient generators of squeezed light. I show by blue and red tuning the two cavities in a double-cavity OMS, one can generate effectively a two-mode parametric interaction which yields two-mode squeezed output with the squeezing magnitude of the order of 10dB. This requires a bath temperature of 10mK. Such temperatures obtained by using Helium dilution refrigerator are routinely used with superconducting OMS. The major part of this dissertation is devoted to the dispersive optomechanical interaction. However, the interaction can also be dissipative, where the mechanical displacement modulates
Squeezed states and Hermite polynomials in a complex variable
International Nuclear Information System (INIS)
Ali, S. Twareque; Górska, K.; Horzela, A.; Szafraniec, F. H.
2014-01-01
Following the lines of the recent paper of J.-P. Gazeau and F. H. Szafraniec [J. Phys. A: Math. Theor. 44, 495201 (2011)], we construct here three types of coherent states, related to the Hermite polynomials in a complex variable which are orthogonal with respect to a non-rotationally invariant measure. We investigate relations between these coherent states and obtain the relationship between them and the squeezed states of quantum optics. We also obtain a second realization of the canonical coherent states in the Bargmann space of analytic functions, in terms of a squeezed basis. All this is done in the flavor of the classical approach of V. Bargmann [Commun. Pure Appl. Math. 14, 187 (1961)
Luminescence and squeezing of a superconducting light-emitting diode
Hlobil, Patrik; Orth, Peter P.
2015-05-01
We investigate a semiconductor p -n junction in contact with superconducting leads that is operated under forward bias as a light-emitting diode. The presence of superconductivity results in a significant increase of the electroluminescence in a sharp frequency window. We demonstrate that the tunneling of Cooper pairs induces an additional luminescence peak on resonance. There is a transfer of superconducting to photonic coherence that results in the emission of entangled photon pairs and squeezing of the fluctuations in the quadrature amplitudes of the emitted light. We show that the squeezing angle can be electrically manipulated by changing the relative phase of the order parameters in the superconductors. We finally derive the conditions for lasing in the system and show that the laser threshold is reduced due to superconductivity. This reveals how the macroscopic coherence of a superconductor can be used to control the properties of light.
QUANTUM MECHANICS. Quantum squeezing of motion in a mechanical resonator.
Wollman, E E; Lei, C U; Weinstein, A J; Suh, J; Kronwald, A; Marquardt, F; Clerk, A A; Schwab, K C
2015-08-28
According to quantum mechanics, a harmonic oscillator can never be completely at rest. Even in the ground state, its position will always have fluctuations, called the zero-point motion. Although the zero-point fluctuations are unavoidable, they can be manipulated. Using microwave frequency radiation pressure, we have manipulated the thermal fluctuations of a micrometer-scale mechanical resonator to produce a stationary quadrature-squeezed state with a minimum variance of 0.80 times that of the ground state. We also performed phase-sensitive, back-action evading measurements of a thermal state squeezed to 1.09 times the zero-point level. Our results are relevant to the quantum engineering of states of matter at large length scales, the study of decoherence of large quantum systems, and for the realization of ultrasensitive sensing of force and motion. Copyright © 2015, American Association for the Advancement of Science.
Deformed two-photon squeezed states in noncommutative space
International Nuclear Information System (INIS)
Zhang Jianzu
2004-01-01
Recent studies on nonperturbation aspects of noncommutative quantum mechanics explored a new type of boson commutation relations at the deformed level, described by deformed annihilation-creation operators in noncommutative space. This correlated boson commutator correlates different degrees of freedom, and shows an essential influence on dynamics. This Letter devotes to the development of formalism of deformed two-photon squeezed states in noncommutative space. General representations of deformed annihilation-creation operators and the consistency condition for the electromagnetic wave with a single mode of frequency in noncommunicative space are obtained. Two-photon squeezed states are studied. One finds that variances of the dimensionless Hermitian quadratures of the annihilation operator in one degree of freedom include variances in the other degree of freedom. Such correlations show the new feature of spatial noncommutativity and allow a deeper understanding of the correlated boson commutator
The POLIS interferometer for ponderomotive squeezed light generation
Energy Technology Data Exchange (ETDEWEB)
Calloni, Enrico [Dipartimento di Fisica, Università degli Studi di Napoli “Federico II”, Napoli (Italy); INFN, Sezione di Napoli (Italy); Conte, Andrea [Dipartimento di Fisica, Università di Roma “Sapienza”, Roma (Italy); INFN, Sezione di Roma1 (Italy); De Laurentis, Martina, E-mail: martina.delaurentis@na.infn.it [Dipartimento di Fisica, Università degli Studi di Napoli “Federico II”, Napoli (Italy); INFN, Sezione di Napoli (Italy); Naticchioni, Luca [Dipartimento di Fisica, Università di Roma “Sapienza”, Roma (Italy); INFN, Sezione di Roma1 (Italy); Puppo, Paola [INFN, Sezione di Roma1 (Italy); Ricci, Fulvio [Dipartimento di Fisica, Università di Roma “Sapienza”, Roma (Italy); INFN, Sezione di Roma1 (Italy)
2016-07-11
POLIS (POnderomotive LIght Squeezer) is a suspended interferometer, presently under construction, devoted to the generation of ponderomotive squeezed light and to the study of the interaction of non classical quantum states of light and macroscopic objects. The interferometer is a Michelson whose half-meter long arms are constituted by high-finesse cavities, suspended to a seismic isolation chain similar to the Virgo SuperAttenuator. The mass of the suspended cavity mirrors are chosen to be tens of grams: this value is sufficiently high to permit the use of the well-tested Virgo suspension techniques but also sufficiently small to generate the coupling among the two phase quadratures with a limited amount of light in the cavity, of the order of few tens of kW. In this short paper the main features of the interferometer are shown, together with the expected sensitivity and squeezing factor.
Encoding qubits into oscillators with atomic ensembles and squeezed light
Motes, Keith R.; Baragiola, Ben Q.; Gilchrist, Alexei; Menicucci, Nicolas C.
2017-05-01
The Gottesman-Kitaev-Preskill (GKP) encoding of a qubit within an oscillator provides a number of advantages when used in a fault-tolerant architecture for quantum computing, most notably that Gaussian operations suffice to implement all single- and two-qubit Clifford gates. The main drawback of the encoding is that the logical states themselves are challenging to produce. Here we present a method for generating optical GKP-encoded qubits by coupling an atomic ensemble to a squeezed state of light. Particular outcomes of a subsequent spin measurement of the ensemble herald successful generation of the resource state in the optical mode. We analyze the method in terms of the resources required (total spin and amount of squeezing) and the probability of success. We propose a physical implementation using a Faraday-based quantum nondemolition interaction.
Globalisation squeezes the public sector - is it so obvious?
DEFF Research Database (Denmark)
Andersen, Torben M.; Sørensen, Allan
It is widely perceived that globalization squeezes public sector activities by making taxation more costly. This is attributed to increased factor mobility and to a more elastic labour demand due to improved scope for relocation of production and thus employment across countries. We argue...... that this consensus view overlooks that gains from trade unambiguously work to lower the marginal costs of public funds, and moreover that globalization via increased trade in intermediaries may actually lower the labour demand elasticity....
Noncritical quadrature squeezing through spontaneous polarization symmetry breaking
Garcia-Ferrer, Ferran V.; Navarrete-Benlloch, Carlos; de Valcárcel, Germán J.; Roldán, Eugenio
2010-01-01
We discuss the possibility of generating noncritical quadrature squeezing by spontaneous polarization symmetry breaking. We consider first type-II frequency-degenerate optical parametric oscillators, but discard them for a number of reasons. Then we propose a four-wave mixing cavity in which the polarization of the output mode is always linear but has an arbitrary orientation. We show that in such a cavity complete noise suppression in a quadrature of the output field occurs, irrespective of ...
Noncritical quadrature squeezing through spontaneous polarization symmetry breaking.
Garcia-Ferrer, Ferran V; Navarrete-Benlloch, Carlos; de Valcárcel, Germán J; Roldán, Eugenio
2010-07-01
We discuss the possibility of generating noncritical quadrature squeezing by spontaneous polarization symmetry breaking. We first consider Type II frequency-degenerate optical parametric oscillators but discard them for a number of reasons. Then we propose a four-wave-mixing cavity, in which the polarization of the output mode is always linear but has an arbitrary orientation. We show that in such a cavity, complete noise suppression in a quadrature of the output field occurs, irrespective of the parameter values.
Possible Depolarization Mechanism due to Low Beta Squeeze
International Nuclear Information System (INIS)
Ranjbar, V.; Luccio, A.; Bai, M.
2008-01-01
Simulations reveal a potential depolarization mechanism during low beta squeeze. This depolarization appears to be driven by a spin tune modulation caused by spin precession through the strong low beta quads due to the vertical fields. The modulation of the spin tune introduces an additional snake resonance condition at ν s0 ± nν x - ν z l = integer which while the same numerology as the well known sextupole resonance, can operate in the absence of sextupole elements
Quantum correlations induced by multiple scattering of quadrature squeezed light
DEFF Research Database (Denmark)
Lodahl, Peter
2006-01-01
Propagating quadrature squeezed light through a multiple scattering random medium is found to induce pronounced spatial quantum correlations that have no classical analogue. The correlations are revealed in the number of photons transported through the sample that can be measured from the intensity...... fluctuations of the total transmission or reflection. In contrast, no pronounced spatial quantum correlations appear in the quadrature amplitudes where excess noise above the shot noise level is found....
Third International Workshop on Squeezed States and Uncertainty Relations
Han, D. (Editor); Kim, Y. S. (Editor); Rubin, Morton H. (Editor); Shih, Yan-Hua (Editor); Zachary, Woodford W. (Editor)
1994-01-01
The purpose of these workshops is to bring together an international selection of scientists to discuss the latest developments in Squeezed States in various branches of physics, and in the understanding of the foundations of quantum mechanics. At the third workshop, special attention was given to the influence that quantum optics is having on our understanding of quantum measurement theory. The fourth meeting in this series will be held in the People's Republic of China.
Sixth International Conference on Squeezed States and Uncertainty Relations
Han, D. (Editor); Kim, Y. S. (Editor); Solimento, S. (Editor)
2000-01-01
These proceedings contain contributions from about 200 participants to the 6th International Conference on Squeezed States and Uncertainty Relations (ICSSUR'99) held in Naples May 24-29, 1999, and organized jointly by the University of Naples "Federico II," the University of Maryland at College Park, and the Lebedev Institute, Moscow. This was the sixth of a series of very successful meetings started in 1990 at the College Park Campus of the University of Maryland. The other meetings in the series were held in Moscow (1992), Baltimore (1993), Taiyuan P.R.C. (1995) and Balatonfuered, Hungary (1997). The present one was held at the campus Monte Sant'Angelo of the University "Federico II" of Naples. The meeting sought to provide a forum for updating and reviewing a wide range of quantum optics disciplines, including device developments and applications, and related areas of quantum measurements and quantum noise. Over the years, the ICSSUR Conference evolved from a meeting on quantum measurement sector of quantum optics, to a wide range of quantum optics themes, including multifacet aspects of generation, measurement, and applications of nonclassical light (squeezed and Schrodinger cat radiation fields, etc.), and encompassing several related areas, ranging from quantum measurement to quantum noise. ICSSUR'99 brought together about 250 people active in the field of quantum optics, with special emphasis on nonclassical light sources and related areas. The Conference was organized in 8 Sections: Squeezed states and uncertainty relations; Harmonic oscillators and squeeze transformations; Methods of quantum interference and correlations; Quantum measurements; Generation and characterisation of non-classical light; Quantum noise; Quantum communication and information; and Quantum-like systems.
International Nuclear Information System (INIS)
Nigro, G; Carbone, V
2015-01-01
Conventional surveys on the existence of singularities in fluid systems for vanishing dissipation have hitherto tried to infer some insight by searching for spatial features developing in asymptotic regimes. This approach has not yet produced a conclusive answer. One of the difficulties preventing us from getting a definitive answer is the limitations of direct numerical simulations which do not yet have a high enough resolution so far as to properly describe spatial fine structures in asymptotic regimes. In this paper, instead of searching for spatial details, we suggest seeking a principle, that would be able to discriminate between singular or not-singular behavior, among the integral and purely dynamical properties of a fluid system. We investigate the singularities developed by a hydromagnetic shell model during the magnetohydrodynamic turbulent cascade. Our results show that when the viscosity is equal to the magnetic diffusivity (unit magnetic Prandtl number) singularities appear in a finite time. A complex behavior is observed at extreme magnetic Prandtl numbers. In particular, the singularities persist in the limit of vanishing viscosity, while a complete regularization is observed in the limit of vanishing diffusivity. This dynamics is related to differences between the magnetic and the kinetic energy cascades towards small scales. Finally a comparison between the three-dimensional and the two-dimensional cases leads to conjecture that the existence of singularities may be related to the conservation of different ideal invariants. (paper)
Directory of Open Access Journals (Sweden)
M. Das
2015-12-01
Full Text Available The influence of Newtonian heating on heat and mass transfer in unsteady hydromagnetic flow of a Casson fluid past a vertical plate in the presence of thermal radiation and chemical reaction is studied. The Casson fluid model is used to distinguish the non-Newtonian fluid behavior. The fluid flow is induced due to periodic oscillations of the plate along its length and a uniform transverse magnetic field is applied in a direction which is normal to the direction of fluid flow. The partial differential equations governing the flow, heat, and mass transfer are transformed to non-dimensional form using suitable non-dimensional variables which are then solved analytically by using Laplace transform technique. The numerical values of the fluid velocity, fluid temperature, and species concentration are depicted graphically whereas the values of skin-friction, Nusselt number, and Sherwood number are presented in tabular form. It is noticed that the fluid velocity and temperature decrease with increasing values of Casson parameter while concentration decreases with increasing values of chemical reaction parameter and Schmidt number. Such a fluid flow model has several industrial and medical applications such as in glass manufacturing, paper production, purification of crude oil and study of blood flow in the cardiovascular system.
An Experimental and numerical Study for squeezing flow
Nathan, Rungun; Lang, Ji; Wu, Qianhong; Vucbmss Team
2017-11-01
We report an experimental and numerical study to examine the transient squeezing flow driven by sudden external impacts. The phenomenon is widely observed in industrial applications, e.g. squeeze dampers, or in biological systems, i.e. joints lubrication. However, there is a lack of investigation that captures the transient flow feature during the process. An experimental setup was developed that contains a piston instrumented with a laser displacement sensor and a pressure transducer. The heavy piston was released from rest, creating a fast compaction on the thin fluid gap underneath. The motion of the piston and the fluid pressure build-up was recorded. For this dynamic process, a CFD simulation was performed which shows excellent agreement with the experimental data. Both the numerical and experimental results show that, the squeezing flow starts with the inviscid limit when the viscous fluid effect has no time to appear, and thereafter becomes a developing flow, in which the inviscid core flow region decreases and the viscous wall region increases until the entire fluid gap is filled with viscous fluid flow. The study presented herein, filling the gap in the literature, will have broad impacts in industrial and biomedical applications. This research was supported by the National Science Foundation under Award 1511096, and supported by the Seed Grant from The Villanova Center for the Advancement of Sustainability in Engineering (VCASE).
China's marriage squeeze: A decomposition into age and sex structure.
Jiang, Quanbao; Li, Xiaomin; Li, Shuzhuo; Feldman, Marcus W
2016-06-01
Most recent studies of marriage patterns in China have emphasized the male-biased sex ratio but have largely neglected age structure as a factor in China's male marriage squeeze. In this paper we develop an index we call "spousal sex ratio" (SSR) to measure the marriage squeeze, and a method of decomposing the proportion of male surplus into age and sex structure effects within a small spousal age difference interval. We project that China's marriage market will be confronted with a relatively severe male squeeze. For the decomposition of the cohort aged 30, from 2010 to 2020 age structure will be dominant, while from 2020 through 2034 the contribution of age structure will gradually decrease and that of sex structure will increase. From then on, sex structure will be dominant. The index and decomposition, concentrated on a specific female birth cohort, can distinguish spousal competition for single cohorts which may be covered by a summary index for the whole marriage market; these can also be used for consecutive cohorts to reflect the situation of the whole marriage market.
Information Entropy Squeezing of a Two-Level Atom Interacting with Two-Mode Coherent Fields
Institute of Scientific and Technical Information of China (English)
LIU Xiao-Juan; FANG Mao-Fa
2004-01-01
From a quantum information point of view we investigate the entropy squeezing properties for a two-level atom interacting with the two-mode coherent fields via the two-photon transition. We discuss the influences of the initial state of the system on the atomic information entropy squeezing. Our results show that the squeezed component number,squeezed direction, and time of the information entropy squeezing can be controlled by choosing atomic distribution angle,the relative phase between the atom and the two-mode field, and the difference of the average photon number of the two field modes, respectively. Quantum information entropy is a remarkable precision measure for the atomic squeezing.
Flower-Like Squeezing in the Motion of a Laser-Driven Trapped Ion
Nguyen, Ba An; Truong, Minh Duc
We investigate the Nth order amplitude squeezing in the fan-state |ξ2k,f>F which is a linear superposition of the 2k-quantum nonlinear coherent states. Unlike in usual states where an ellipse is the symbol of squeezing, a 4k-winged flower results in the fan state. We first derive the analytical expression of squeezing for arbitrary k, N, f and then study in detail the case of a laser-driven trapped ion characterized by a specific form of the nonlinear function f. We show that the lowest order in which squeezing may appear and the number of directions along which the amplitude may be squeezed depend only on k whereas the precise directions of squeezing are determined also by the other physical parameters involved. Finally, we present a scheme to produce such fan-states.
A group property for the coherent state representation of fermionic squeezing operators
Fan, Hong-yi; Li, Chao
2004-06-01
For the two-mode fermionic squeezing operators we find that their coherent state projection operator representation make up a loyal representation, which is homomorphic to an SO(4) group, though the fermionic coherent states are not mutual orthogonal. Thus the result of successively operating with many fermionic squeezing operators on a state can be equivalent to a single operation. The fermionic squeezing operators are mappings of orthogonal transformations in Grassmann number pseudo-classical space in the fermionic coherent state representation.
A group property for the coherent state representation of fermionic squeezing operators
International Nuclear Information System (INIS)
Fan Hongyi; Li Chao
2004-01-01
For the two-mode fermionic squeezing operators we find that their coherent state projection operator representation make up a loyal representation, which is homomorphic to an SO(4) group, though the fermionic coherent states are not mutual orthogonal. Thus the result of successively operating with many fermionic squeezing operators on a state can be equivalent to a single operation. The fermionic squeezing operators are mappings of orthogonal transformations in Grassmann number pseudo-classical space in the fermionic coherent state representation
Spin squeezing of atomic ensembles via nuclear-electronic spin entanglement
DEFF Research Database (Denmark)
Fernholz, Thomas; Krauter, Hanna; Jensen, Kasper
2008-01-01
quantum limit for quantum memory experiments and applications in quantum metrology and is thus a complementary alternative to spin squeezing obtained via inter-atom entanglement. Squeezing of the collective spin is verified by quantum state tomography.......We demonstrate spin squeezing in a room temperature ensemble of 1012 Cesium atoms using their internal structure, where the necessary entanglement is created between nuclear and electronic spins of each individual atom. This state provides improvement in measurement sensitivity beyond the standard...
Foamed cement for squeeze cementing low-pressure, highly permeable reservoirs
International Nuclear Information System (INIS)
Chmllowski, W.; Kondratoff, L.B.
1992-01-01
Four different cement squeezing techniques have been used on wells producing from the Keg River formation in the Rainbow Lake area of Alberta, Canada. This paper evaluates 151 cement squeeze treatments performed at 96 wellsites and compares the use of foam cement vs. conventional squeeze treatments and techniques. Discussion includes key aspects, such as candidate selection, slurry design, treatment design, economic evaluation, and operational considerations
On the Generation of Intermediate Number Squeezed State of the Quantized Radiation Field
Baseia, B.; de Lima, A. F.; Bagnato, V. S.
Recently, a new state of the quantized radiation field — the intermediate number squeezed state (INSS) — has been introduced in the literature: it interpolates between the number state |n> and the squeezed state |z, α>=Ŝ(z)|α>, and exhibits interesting nonclassical properties as antibunching, sub-Poissonian statistics and squeezing. Here we introduce a slight modification in the previous definition allowing us a proposal to generate the INSS. Nonclassical properties using a new set of parameters are also studied.
Optimization of Squeeze Casting Parameters for 2017 A Wrought Al Alloy Using Taguchi Method
Directory of Open Access Journals (Sweden)
Najib Souissi
2014-04-01
Full Text Available This study applies the Taguchi method to investigate the relationship between the ultimate tensile strength, hardness and process variables in a squeeze casting 2017 A wrought aluminium alloy. The effects of various casting parameters including squeeze pressure, melt temperature and die temperature were studied. Therefore, the objectives of the Taguchi method for the squeeze casting process are to establish the optimal combination of process parameters and to reduce the variation in quality between only a few experiments. The experimental results show that the squeeze pressure significantly affects the microstructure and the mechanical properties of 2017 A Al alloy.
Higher-order amplitude squeezing of photons propagating through a semiconductor
International Nuclear Information System (INIS)
Nguyen Ba An.
1996-12-01
Photon amplitude K th power squeezing is studied when the coherent photon propagates through a semiconductor containing the exciton. If the exciton is prepared initially in a coherent state, the photon may become amplitude K th power squeezed. It is shown that, in the short-time limit, the photon squeezing in the P direction does not appear at all while that in the X direction is possible for all the amplitude power K. In the latter case, the amount of squeezing is larger for higher power K. Dependences on all the system parameters as well as on the output light detection moment are investigated in detail. (author). 14 refs, 8 figs
Interaction of a quantum well with squeezed light: Quantum-statistical properties
International Nuclear Information System (INIS)
Sete, Eyob A.; Eleuch, H.
2010-01-01
We investigate the quantum statistical properties of the light emitted by a quantum well interacting with squeezed light from a degenerate subthreshold optical parametric oscillator. We obtain analytical solutions for the pertinent quantum Langevin equations in the strong-coupling and low-excitation regimes. Using these solutions we calculate the intensity spectrum, autocorrelation function, and quadrature squeezing for the fluorescent light. We show that the fluorescent light exhibits bunching and quadrature squeezing. We also show that the squeezed light leads to narrowing of the width of the spectrum of the fluorescent light.
Experimental test of the strongly nonclassical character of a noisy squeezed single-photon state
DEFF Research Database (Denmark)
Jezek, M.; Tipsmark, A.; Dong, R.
2012-01-01
We experimentally verify the quantum non-Gaussian character of a conditionally generated noisy squeezed single-photon state with a positive Wigner function. Employing an optimized witness based on probabilities of squeezed vacuum and squeezed single-photon states, we prove that the state cannot...... be expressed as a mixture of Gaussian states. In our experiment, the non-Gaussian state is generated by conditional subtraction of a single photon from a squeezed vacuum state. The state is probed with a homodyne detector and the witness is determined by averaging a suitable pattern function over the measured...
Enhanced squeezing of a collective spin via control of its qudit subsystems.
Norris, Leigh M; Trail, Collin M; Jessen, Poul S; Deutsch, Ivan H
2012-10-26
Unitary control of qudits can improve the collective spin squeezing of an atomic ensemble. Preparing the atoms in a state with large quantum fluctuations in magnetization strengthens the entangling Faraday interaction. The resulting increase in interatomic entanglement can be converted into metrologically useful spin squeezing. Further control can squeeze the internal atomic spin without compromising entanglement, providing an overall multiplicative factor in the collective squeezing. We model the effects of optical pumping and study the tradeoffs between enhanced entanglement and decoherence. For realistic parameters we see improvements of ~10 dB.
Squeezed light in an optical parametric oscillator network with coherent feedback quantum control.
Crisafulli, Orion; Tezak, Nikolas; Soh, Daniel B S; Armen, Michael A; Mabuchi, Hideo
2013-07-29
We present squeezing and anti-squeezing spectra of the output from a degenerate optical parametric oscillator (OPO) network arranged in different coherent quantum feedback configurations. One OPO serves as a quantum plant, the other as a quantum controller. The addition of coherent feedback enables shaping of the output squeezing spectrum of the plant, and is found to be capable of pushing the frequency of maximum squeezing away from the optical driving frequency and broadening the spectrum over a wider frequency band. The experimental results are in excellent agreement with the developed theory, and illustrate the use of coherent quantum feedback to engineer the quantum-optical properties of the plant OPO output.
Directory of Open Access Journals (Sweden)
Schnabel Roman
2013-08-01
Full Text Available This contribution reviews our recent progress on the generation of squeezed light [1], and also the recent squeezed-light enhancement of the gravitational wave detector GEO 600 [2]. GEO 600 is currently the only GW observatory operated by the LIGO Scientific Collaboration in its search for gravitational waves. With the help of squeezed states of light it now operates with its best ever sensitivity, which not only proves the qualification of squeezed light as a key technology for future gravitational wave astronomy but also the usefulness of quantum entanglement.
Manipulation of Squeezed Two-Phonon Bound States using Femtosecond Laser Pulses
Directory of Open Access Journals (Sweden)
Nakamura Kazutaka G.
2013-03-01
Full Text Available Two-phonon bound states have been excited exclusively in ZnTe(110 via impulsive stimulated second-order Raman scattering, essentially being squeezed states due to phase coherent excitation of two identical components anticorrelated in the wave vector. By using coherent control technique with a pair of femtosecond laser pulses, the manipulation of squeezed states has been demonstrated in which both the amplitude and lifetime of coherent oscillations of squeezed states are modulated, indicating the feasibility to control the quantum noise and the quantum nature of phonon squeezed states, respectively.
Squeezing survival and transfer in single and double electromagnetically induced transparency
International Nuclear Information System (INIS)
Ding, J L; Hou, B P; Wang, S J
2010-01-01
We investigate the propagation and storage of a squeezed vacuum as the probe light in a collection of N four-level tripod configuration atoms under the condition of single or double electromagnetically induced transparency (EIT). The squeezing of the probe light is well preserved in both the single transparency channel and the double transparency one. On the other hand, the effects of the ground state dephasing rates on the propagation and storage of the squeezed vacuum are investigated. It is found that the maximum squeezing at the transparency points is suppressed by the dephasing rates in single or double EIT. Meanwhile, the mapping of the squeezing of the probe light onto the atomic ground coherences or onto the two atomic dark-state polaritons is also studied. In the absence of the Langevin atomic noise, the quasi-ideal squeezing transfer between the squeezed vacuum and the atomic ground coherences or the dark-state polaritons can be realized in such a system. When considering the Langevin atomic noise, the quantum characteristics of the atomic coherences at resonance are submerged by the Langevin noise, while in the scenario of the dark-state polariton, it is found that squeezing transfer onto one polariton is damaged, but the squeezing transfer onto the other polariton survives even in the presence of the Langevin noise.
A low loss Faraday isolator for squeezed vacuum injection in Advanced LIGO
Goetz, Ryan; Tanner, David; Mueller, Guido
2016-03-01
Using conventional interferometry, the strain sensitivity of Advanced LIGO is limited by a quantum noise floor known as the standard quantum limit (SQL). Injecting squeezed vacuum states into the output port of the interferometer allows for detector sensitivities below the SQL at frequencies within a band of observational interest. The effectiveness of squeezing in reducing quantum noise is strongly dependent upon the optical loss in the squeezed path. Thus, to combine the squeezed vacuum state with the interferometer output we require a Faraday isolator with both high power-throughput efficiency and high isolation ratio. A prototype isolator is currently being developed, and we will discuss the design goals and current status.
International Nuclear Information System (INIS)
Chamkha, Ali J.; Al-Rashidi, Seham S.
2010-01-01
This work considers the problem of steady natural convection hydromagnetic flow of a particulate suspension through an infinitely long channel in the presence of heat generation or absorption effects. The channel walls are maintained at isoflux-isothermal condition. That is, the thermal boundary conditions are such that one of the channel walls is maintained at constant heat flux while the other is maintained at a constant temperature. Various closed-form solutions of the governing equations for different special cases are obtained. A parametric study of the physical parameters involved in the problem is done to illustrate the influence of these parameters on the velocity and temperature profiles of both phases.
Directory of Open Access Journals (Sweden)
Sandeep Naramgari
2014-01-01
Full Text Available We analyse the effects of aligned magnetic field, radiation, and rotation on unsteady hydromagnetic free convection flow of a viscous incompressible electrically conducting fluid past an impulsively moving vertical plate in a porous medium in presence of heat source. An exact solution of the governing equations in dimensionless form is obtained by Laplace transform technique in ramped temperature case. To compare the results obtained in this case with that of isothermal plate, the exact solution of the governing equations is also obtained for isothermal plate and results are discussed graphically in both ramped temperature and isothermal cases.
International Nuclear Information System (INIS)
Mikhailov, Eugeniy E.; Goda, Keisuke; Corbitt, Thomas; Mavalvala, Nergis
2006-01-01
We study the effects of frequency-dependent squeeze-amplitude attenuation and squeeze-angle rotation by electromagnetically induced transparency (EIT) on gravitational-wave (GW) interferometers. We propose the use of low-pass, bandpass, and high-pass EIT filters, an S-shaped EIT filter, and an intracavity EIT filter to generate frequency-dependent squeezing for injection into the antisymmetric port of GW interferometers. We find that the EIT filters have several advantages over the previous filter designs with regard to optical losses, compactness, and the tunability of the filter linewidth
Optimal unambiguous comparison of two unknown squeezed vacua
International Nuclear Information System (INIS)
Olivares, Stefano; Paris, Matteo G. A.; Sedlak, Michal; Rapsan, Peter; Busek, Vladimir
2011-01-01
We propose a scheme for the unambiguous state comparison (USC) of two unknown squeezed vacuum states of the electromagnetic field. Our setup is based on linear optical elements and photon-number detectors, and it achieves optimal USC in an ideal case of unit quantum efficiency. In realistic conditions, i.e., for nonunit quantum efficiency of photodetectors, we evaluate the probability of getting an ambiguous result as well as the reliability of the scheme, thus showing its robustness in comparison to previous proposals.
Oscillatory squeeze flow for the study of linear viscoelastic behavior
DEFF Research Database (Denmark)
Wingstrand, Sara Lindeblad; Alvarez, Nicolas J.; Hassager, Ole
2016-01-01
of molten polymers and suspensions. The principal advantage of squeeze flow rheometer over rotational devices is the simplicity of the apparatus. It has no air bearing and is much less expensive and easier to use. Accuracy may be somewhat reduced, but for quality control purposes, it could be quite useful....... It might also find application as the central component of a high-throughput rheometer for evaluating experimental materials. The deformation is not simple shear, but equations have been derived to show that the oscillatory compressive (normal) force that is measured can serve as a basis for calculating...
Lipid corralling and poloxamer squeeze-out in membranes
DEFF Research Database (Denmark)
Wu, G.H.; Majewski, J.; Ege, C.
2004-01-01
Using x-ray scattering measurements we have quantitatively determined the effect of poloxamer 188 (P188), a polymer known to seal damaged membranes, on the structure of lipid monolayers. P188 selectively inserts into low lipid-density regions of the membrane and "corrals" lipid molecules to pack...... tightly, leading to unexpected Bragg peaks at low nominal lipid density and inducing lipid/poloxamer phase separation. At tighter lipid packing, the once inserted P188 is squeezed out, allowing the poloxamer to gracefully exit when the membrane integrity is restored....
Light squeezing through arbitrarily shaped plasmonic channels and sharp bends
International Nuclear Information System (INIS)
Alu, Andrea; Engheta, Nader
2008-01-01
We propose a mechanism for optical energy squeezing and anomalous light transmission through arbitrarily-shaped plasmonic ultranarrow channels and bends connecting two larger plasmonic metal-insulator-metal waveguides. It is shown how a proper design of subwavelength optical channels at cutoff, patterned by plasmonic implants and connecting larger plasmonic waveguides, may allow enhanced resonant transmission inspired by the anomalous properties of epsilon-near-zero (ENZ) metamaterials. The resonant transmission is shown to be only weakly dependent on the channel length and its specific geometry, such as possible presence of abruptions and bends
Colliding During the Squeeze and β* Levelling in the LHC
Buffat, X; Lamont, M; Pieloni, T; Redaelli, S; Wenninger, J
2013-01-01
While significantly more complicated in term of operation, bringing the beams into collisions prior to the β squeeze rather than after presents some advantages. Indeed, the large tune spread arising from the non-linearity of head-on beam-beam interactions is profitable, as it can damp impedance driven instabilities much more efficiently than external non-linearity such as octupoles. Moreover, this operation allows to level the luminosity in the case when the peak luminosity is too high for the experiments. Operational issues are discussed and experimental results from the LHC are presented.
Quadrature measurements of a bright squeezed state via sideband swapping
DEFF Research Database (Denmark)
Schneider, J.; Glockl, O.; Leuchs, G.
2009-01-01
The measurement of an arbitrary quadrature of a bright quantum state of light is a commonly requested action in many quantum information protocols, but it is experimentally challenging with previously proposed schemes. We suggest that the quadrature be measured at a specific sideband frequency...... of a bright quantum state by transferring the sideband modes under interrogation to a vacuum state and subsequently measuring the quadrature via homodyne detection. The scheme is implemented experimentally, and it is successfully tested with a bright squeezed state of light....
All-fibre source of amplitude squeezed light pulses
Energy Technology Data Exchange (ETDEWEB)
Meissner, Markus; Marquardt, Christoph; Heersink, Joel; Gaber, Tobias; Wietfeld, Andre; Leuchs, Gerd; Andersen, Ulrik L [Institut fuer Optik, Information und Photonik, Max-Planck Forschungsgruppe Universitaet Erlangen-Nuernberg, Staudtstrasse 7/B2, 91058, Erlangen (Germany)
2004-08-01
An all-fibre source of amplitude squeezed solitons utilizing the self-phase modulation in an asymmetric Sagnac interferometer is experimentally demonstrated. The asymmetry of the interferometer is passively controlled by an integrated fibre coupler, allowing for the optimization of the noise reduction. We have carefully studied the dependence of the amplitude noise on the asymmetry and the power launched into the Sagnac interferometer. Qualitatively, we find good agreement between the experimental results, a semi-classical theory and earlier numerical calculations (Schmitt et al 1998 Phys. Rev. Lett. 81 2446). The stability and flexibility of this all-fibre source makes it particularly well suited to applications in quantum information science.
Variance squeezing and entanglement of the XX central spin model
International Nuclear Information System (INIS)
El-Orany, Faisal A A; Abdalla, M Sebawe
2011-01-01
In this paper, we study the quantum properties for a system that consists of a central atom interacting with surrounding spins through the Heisenberg XX couplings of equal strength. Employing the Heisenberg equations of motion we manage to derive an exact solution for the dynamical operators. We consider that the central atom and its surroundings are initially prepared in the excited state and in the coherent spin state, respectively. For this system, we investigate the evolution of variance squeezing and entanglement. The nonclassical effects have been remarked in the behavior of all components of the system. The atomic variance can exhibit revival-collapse phenomenon based on the value of the detuning parameter.
Normalized Excited Squeezed Vacuum State and Its Applications
International Nuclear Information System (INIS)
Meng Xiangguo; Wang Jisuo; Liang Baolong
2007-01-01
By using the intermediate coordinate-momentum representation in quantum optics and generating function for the normalization of the excited squeezed vacuum state (ESVS), the normalized ESVS is obtained. We find that its normalization constants obtained via two new methods are uniform and a new form which is different from the result obtained by Zhang and Fan [Phys. Lett. A 165 (1992) 14]. By virtue of the normalization constant of the ESVS and the intermediate coordinate-momentum representation, the tomogram of the normalized ESVS and some useful formulae are derived.
Variance squeezing and entanglement of the XX central spin model
Energy Technology Data Exchange (ETDEWEB)
El-Orany, Faisal A A [Department of Mathematics and Computer Science, Faculty of Science, Suez Canal University, Ismailia (Egypt); Abdalla, M Sebawe, E-mail: m.sebaweh@physics.org [Mathematics Department, College of Science, King Saud University PO Box 2455, Riyadh 11451 (Saudi Arabia)
2011-01-21
In this paper, we study the quantum properties for a system that consists of a central atom interacting with surrounding spins through the Heisenberg XX couplings of equal strength. Employing the Heisenberg equations of motion we manage to derive an exact solution for the dynamical operators. We consider that the central atom and its surroundings are initially prepared in the excited state and in the coherent spin state, respectively. For this system, we investigate the evolution of variance squeezing and entanglement. The nonclassical effects have been remarked in the behavior of all components of the system. The atomic variance can exhibit revival-collapse phenomenon based on the value of the detuning parameter.
Squeezing of higher order Hermite-Gauss modes
DEFF Research Database (Denmark)
Lassen, Mikael Østergaard
2008-01-01
The present paper gives an overview of the experimental generation of squeezing in higher order Hermite-Gaussian modes with an optical parametric ampli¯er (OPA). This work was awarded with The European Optical Society (EOS) price 2007. The purpose of the prize is to encourage a European dimension...... in research in pure and applied optics. The EOS prize is awarded based on the selection criteria of high professionalism, academic and technical quality. Following the EOS Prize rules, the conditions for eligibility are that the work was performed in Europe and that it is published under the auspices...
On irreversible evolutions of two-level systems approaching coherent and squeezed states
International Nuclear Information System (INIS)
Jurco, B.; Tolar, J.
1988-01-01
The concepts of completely positive quantum dynamical semigroups and SU(2)-related generalized coherence and squeezing are used to investigate conditions for Markovian evolutions leading to coherent, intelligent, minimum-uncertainty and squeezed asymptotic stationary states in a 2-level system. (author). 10 refs
New Three-Mode Squeezing Operators Gained via Tripartite Entangled State Representation
International Nuclear Information System (INIS)
Jiang Nianquan; Fan Hongyi
2008-01-01
We show that the Agarwal-Simon representation of single-mode squeezed states can be generalized to find new form of three-mode squeezed states. We use the tripartite entangled state representations |p,y,z> and |x,u,v> to realize this goal.
SU(2) and SU(1,1) squeezing of interacting radiation modes
International Nuclear Information System (INIS)
Abdalla Sebawe, M.; Faisal El-Orany, A.A.; Perina, J.
2000-01-01
In this communication we discuss SU(1,1) and SU(2) squeezing of an interacting system of radiation modes in a quadratic medium in the framework of Lie algebra. We show that regardless of which state being initially considered, squeezing can be periodically generated. (authors)
Measurement Induced Enhancement of Squeezing in Nondegenerate Two-Photon Jaynes-Cummings Model
International Nuclear Information System (INIS)
Ye Saiyun
2006-01-01
Squeezing properties in the nondegenerate two-photon Jaynes-Cummings model are investigated. The effects of direct selective atomic measurement and the application of the classical field followed by atomic measurement are analyzed. Different values of the parameters of the classical field are taken into account. It is found that the field squeezing can be enhanced by measurement.
Nonlinear modeling and testing of magneto-rheological fluids in low shear rate squeezing flows
International Nuclear Information System (INIS)
Farjoud, Alireza; Ahmadian, Mehdi; Craft, Michael; Mahmoodi, Nima; Zhang, Xinjie
2011-01-01
A novel analytical investigation of magneto-rheological (MR) fluids in squeezing flows is performed and the results are validated with experimental test data. The squeeze flow of MR fluids has recently been of great interest to researchers. This is due to the large force capacity of MR fluids in squeeze mode compared to other modes (valve and shear modes), which makes the squeeze mode appropriate for a wide variety of applications such as impact dampers and engine mounts. Tested MR fluids were capable of providing a large range of controllable force along a short stroke in squeeze mode. A mathematical model was developed using perturbation techniques to predict closed-form solutions for velocity field, shear rate distribution, pressure distribution and squeeze force. Therefore, the obtained solutions greatly help with the design process of intelligent devices that use MR fluids in squeeze mode. The mathematical model also reduces the need for complicated and computationally expensive numerical simulations. The analytical results are validated by performing experimental tests on a novel MR device called an 'MR pouch' in an MR squeeze mode rheometer, both designed and built at CVeSS
Experimental evidence for Raman-induced limits to efficient squeezing in optical fibers
DEFF Research Database (Denmark)
Dong, R.; Heersink, J.; Corney, J.
2008-01-01
We report new experiments on polarization squeezing using ultrashort photonic pulses in a single pass of a birefringent fiber. We measure what is to our knowledge a record squeezing of -6.8 +/- 0.3 dB in optical fibers which when corrected for linear losses is -10.4 +/- 0.8 dB. The measured polar...
Spin squeezing as an indicator of quantum chaos in the Dicke model.
Song, Lijun; Yan, Dong; Ma, Jian; Wang, Xiaoguang
2009-04-01
We study spin squeezing, an intrinsic quantum property, in the Dicke model without the rotating-wave approximation. We show that the spin squeezing can reveal the underlying chaotic and regular structures in phase space given by a Poincaré section, namely, it acts as an indicator of quantum chaos. Spin squeezing vanishes after a very short time for an initial coherent state centered in a chaotic region, whereas it persists over a longer time for the coherent state centered in a regular region of the phase space. We also study the distribution of the mean spin directions when quantum dynamics takes place. Finally, we discuss relations among spin squeezing, bosonic quadrature squeezing, and two-qubit entanglement in the dynamical processes.
First beam test of a combined ramp and squeeze at LHC
Wenninger, Jorg; Coello De Portugal - Martinez Vazquez, Jaime Maria; Gorzawski, Arkadiusz; Redaelli, Stefano; Schaumann, Michaela; Solfaroli Camillocci, Matteo; CERN. Geneva. ATS Department
2015-01-01
With increasing maturity of LHC operation it is possible to envisage more complex beam manipulations. At the same time operational efficiency receives increasing attention. So far ramping the beams to their target energy and squeezing the beams to smaller or higher beta are decoupled at the LHC. (De-)squeezing is always performed at the target energy, currently 6.5 TeV. Studies to combine the ramp and squeeze processes have been made for the LHC since 2011, but so far no experimental test with beam had ever performed. This note describes the first machine experiment with beam aiming at validating the combination of ramp and squeeze, the so-called combined ramp and squeeze (CRS).
Influence of the virtual photon field on the squeezing properties of an atom laser
International Nuclear Information System (INIS)
Jian-Gang, Zhao; Chang-Yong, Sun; Ling-Hua, Wen; Bao-Long, Liang
2009-01-01
This paper investigates the squeezing properties of an atom laser without rotating-wave approximation in the system of a binomial states field interacting with a two-level atomic Bose–Einstein condensate. It discusses the influences of atomic eigenfrequency, the interaction intensity between the optical field and atoms, parameter of the binomial states field and virtual photon field on the squeezing properties. The results show that two quadrature components of an atom laser can be squeezed periodically. The duration and the degree of squeezing an atom laser have something to do with the atomic eigenfrequency and the parameter of the binomial states field, respectively. The collapse and revival frequency of atom laser fluctuation depends on the interaction intensity between the optical field and atoms. The effect of the virtual photon field deepens the depth of squeezing an atom laser
International Nuclear Information System (INIS)
Li Xizeng; Shan Ying; Mandel, L.
1988-11-01
It is found that the field of the combined mode of the probe wave and the phase-conjugate wave in the process of degenerate four-wave mixing exhibits higher-order squeezing to all even order. The degree of squeezing increases with the order N, and the higher-order squeeze parameter q N may approach -1. (author). 3 refs, 2 figs
Energy Technology Data Exchange (ETDEWEB)
Jin, G R; Wang, X W; Li, D; Lu, Y W, E-mail: grjin@bjtu.edu.c [Department of Physics, Beijing Jiaotong University, Beijing 100044 (China)
2010-02-28
We investigate spin dynamics of a two-component Bose-Einstein condensate with weak Josephson coupling. Analytical expressions of atom-number squeezing and bipartite entanglement are presented for atom-atom repulsive interactions. For attractive interactions, there is no number squeezing; however, the squeezing parameter is still useful to recognize the appearance of Schroedinger's cat state.
Nanoscale Trapping and Squeeze-Out of Confined Alkane Monolayers.
Gosvami, N N; O'Shea, S J
2015-12-01
We present combined force curve and conduction atomic force microscopy (AFM) data for the linear alkanes CnH2n+2 (n = 10, 12, 14, 16) confined between a gold-coated AFM tip and a graphite surface. Solvation layering is observed in the force curves for all liquids, and conduction AFM is used to study in detail the removal of the confined (mono)layer closest to the graphite surface. The squeeze-out behavior of the monolayer can be very different depending upon the temperature. Below the monolayer melting transition temperatures the molecules are in an ordered state on the graphite surface, and fast and complete removal of the confined molecules is observed. However, above the melting transition temperature the molecules are in a disordered state, and even at large applied pressure a few liquid molecules are trapped within the tip-sample contact zone. These findings are similar to a previous study for branched alkanes [ Gosvami Phys. Rev. Lett. 2008, 100, 076101 ], but the observation for the linear alkane homologue series demonstrates clearly the dependence of the squeeze-out and trapping on the state of the confined material.
Finite Element Analysis of Laser Engineered Net Shape (LENS™) Tungsten Clad Squeeze Pins
Sakhuja, Amit; Brevick, Jerald R.
2004-06-01
In the aluminum high-pressure die-casting and indirect squeeze casting processes, local "squeeze" pins are often used to minimize internal solidification shrinkage in heavy casting sections. Squeeze pins frequently fail in service due to molten aluminum adhering to the H13 tool steel pins ("soldering"). A wide variety of coating materials and methods have been developed to minimize soldering on H13. However, these coatings are typically very thin, and experience has shown their performance on squeeze pins is highly variable. The LENS™ process was employed in this research to deposit a relatively thick tungsten cladding on squeeze pins. An advantage of this process was that the process parameters could be precisely controlled in order to produce a satisfactory cladding. Two fixtures were designed and constructed to enable the end and outer diameter (OD) of the squeeze pins to be clad. Analyses were performed on the clad pins to evaluate the microstructure and chemical composition of the tungsten cladding and the cladding-H13 substrate interface. A thermo-mechanical finite element analysis (FEA) was performed to assess the stress distribution as a function of cladding thickness on the pins during a typical casting thermal cycle. FEA results were validated via a physical test, where the clad squeeze pins were immersed into molten aluminum. Pins subjected to the test were evaluated for thermally induced cracking and resistance to soldering of the tungsten cladding.
Finite element analysis of laser engineered net shape (LENSTM) tungsten clad squeeze pins
International Nuclear Information System (INIS)
Sakhuja, Amit; Brevick, Jerald R.
2004-01-01
In the aluminum high-pressure die-casting and indirect squeeze casting processes, local 'squeeze' pins are often used to minimize internal solidification shrinkage in heavy casting sections. Squeeze pins frequently fail in service due to molten aluminum adhering to the H13 tool steel pins ('soldering'). A wide variety of coating materials and methods have been developed to minimize soldering on H13. However, these coatings are typically very thin, and experience has shown their performance on squeeze pins is highly variable. The LENS TM process was employed in this research to deposit a relatively thick tungsten cladding on squeeze pins. An advantage of this process was that the process parameters could be precisely controlled in order to produce a satisfactory cladding. Two fixtures were designed and constructed to enable the end and outer diameter (OD) of the squeeze pins to be clad. Analyses were performed on the clad pins to evaluate the microstructure and chemical composition of the tungsten cladding and the cladding-H13 substrate interface. A thermo-mechanical finite element analysis (FEA) was performed to assess the stress distribution as a function of cladding thickness on the pins during a typical casting thermal cycle. FEA results were validated via a physical test, where the clad squeeze pins were immersed into molten aluminum. Pins subjected to the test were evaluated for thermally induced cracking and resistance to soldering of the tungsten cladding
Yuan, Sihan; Eisenstein, Daniel J.; Garrison, Lehman H.
2018-04-01
We present the GeneRalized ANd Differentiable Halo Occupation Distribution (GRAND-HOD) routine that generalizes the standard 5 parameter halo occupation distribution model (HOD) with various halo-scale physics and assembly bias. We describe the methodology of 4 different generalizations: satellite distribution generalization, velocity bias, closest approach distance generalization, and assembly bias. We showcase the signatures of these generalizations in the 2-point correlation function (2PCF) and the squeezed 3-point correlation function (squeezed 3PCF). We identify generalized HOD prescriptions that are nearly degenerate in the projected 2PCF and demonstrate that these degeneracies are broken in the redshift-space anisotropic 2PCF and the squeezed 3PCF. We also discuss the possibility of identifying degeneracies in the anisotropic 2PCF and further demonstrate the extra constraining power of the squeezed 3PCF on galaxy-halo connection models. We find that within our current HOD framework, the anisotropic 2PCF can predict the squeezed 3PCF better than its statistical error. This implies that a discordant squeezed 3PCF measurement could falsify the particular HOD model space. Alternatively, it is possible that further generalizations of the HOD model would open opportunities for the squeezed 3PCF to provide novel parameter measurements. The GRAND-HOD Python package is publicly available at https://github.com/SandyYuan/GRAND-HOD.
Impact of quantum–classical correspondence on entanglement enhancement by single-mode squeezing
International Nuclear Information System (INIS)
Joseph, Sijo K.; Chew, Lock Yue; Sanjuán, Miguel A.F.
2014-01-01
Quantum entanglement between two field modes can be achieved through the collective squeezing of the two respective modes. If single-mode squeezing is performed prior to such a two-mode squeezing, an enhancement of entanglement production can happen. Interestingly, the occurrence of this enhancement can be implicitly linked to the local classical dynamical behavior via the paradigm of quantum–classical correspondence. In particular, the entanglement generated through quantum chaos is found to be hardly enhanced by prior squeezing, since it is bounded by the saturation value of the maximally entangled Schmidt state with fixed energy. These results illustrate that entanglement enhancement via initial squeezing can serve as a useful indicator of quantum chaotic behaviour. - Highlights: • Continuous-variable entanglement is explored in the Pullen–Edmonds Hamiltonian. • The local phase-space structure and the entanglement enhancement are related. • Entanglement enhancement via squeezing is smaller for the chaotic orbit. • Entanglement enhancement via squeezing is higher for the regular orbit. • The magnitude of the entanglement enhancement serves as a quantum-chaos indicator
Resonance fluorescence spectra of three-level atoms in a squeezed vacuum
International Nuclear Information System (INIS)
Ferguson, M.R.; Ficek, Z.; Dalton, B.J.
1996-01-01
The fluorescence field from one of the two allowed transitions in a three-level atom can sense squeezed fluctuations of a vacuum field coupled to the other transition. We examine the fluorescence spectra of strongly driven three-level atoms in Λ, V, and cascade configurations in which one of the two one-photon transitions is coupled to a finite-bandwidth squeezed vacuum field, when the bandwidth is much smaller than the difference in the atomic transition frequencies, though much larger than atomic decay rates and Rabi frequencies of the driving fields. The driving fields are on one-photon resonance, and the squeezed vacuum field is generated by a degenerate parameter oscillator. Details are only given for the Λ configuration. The extension to the V and cascade configurations is straightforward. We find that in all configurations the fluorescence spectra of the transition not coupled to the squeezed vacuum field are composed of five lines, one central and two pairs of sidebands, with intensities and widths strongly influenced by the squeezed vacuum field. However, only the central component and the outer sidebands exhibit a dependence on the squeezing phase. We also examine the fluorescence spectrum for the cascade configuration with a squeezed vacuum field on resonance with the two-photon transition between the ground and the most excited states and now generated by a nondegenerate parametric oscillator. In this case, where the squeezed vacuum field can be made coupled to both transitions, all spectral lines depend on the squeezing phase. The spectral features are explained in terms of the dressed-atom model of the system. We show that the coherent mixing of the atomic states by the strong driving fields modifies transition rates between the dressed states, which results in the selective phase dependence of the spectral features. copyright 1996 The American Physical Society
Squeeze casting of aluminum alloy A380: Microstructure and tensile behavior
Directory of Open Access Journals (Sweden)
Li Fang
2015-09-01
Full Text Available A380 alloy with a relatively thick cross-section of 25 mm was squeeze cast using a hydraulic press with an applied pressure of 90 MPa. Microstructure and tensile properties of the squeeze cast A380 were characterized and evaluated in comparison with the die cast counterpart. Results show that the squeeze cast A380 possesses a porosity level much lower than the die cast alloy, which is disclosed by both optical microscopy and the density measurement technique. The results of tensile testing indicate the improved tensile properties, specifically ultimate tensile strength (UTS: 215.9 MPa and elongation (Ef: 5.4%, for the squeeze cast samples over those of the conventional high-pressure die cast part (UTS: 173.7 MPa, Ef: 1.0%. The analysis of tensile behavior shows that the squeeze cast A380 exhibits a high tensile toughness (8.5 MJ·m-3 and resilience (179.3 kJ·m-3 compared with the die cast alloy (toughness: 1.4 MJ·m-3, resilience: 140.6 kJ·m-3, despite that, during the onset of plastic deformation, the strain-hardening rate of the die cast specimen is higher than that of the squeeze cast specimens. The microstructure analyzed by the scanning electron microscopy (SEM shows that both the squeeze and die cast specimens contain the primary α-Al, Al2Cu, Al5FeSi phase and the eutectic Si phase. But, the Al2Cu phase present in the squeeze cast alloy is relatively large in size and quantity. The SEM fractography evidently reveals the ductile fracture features of the squeeze cast A380 alloy.
Viscosity of particle laden films
Timounay, Yousra; Rouyer, Florence
2017-06-01
We perform retraction experiments on soap films where large particles bridge the two interfaces. Local velocities are measured by PIV during the unstationnary regime. The velocity variation in time and space can be described by a continuous fluid model from which effective viscosity (shear and dilatational) of particulate films is measured. The 2D effective viscosity of particulate films η2D increases with particle surface fraction ϕ: at low ϕ, it tends to the interfacial dilatational viscosity of the liquid/air interfaces and it diverges at the critical particle surface fraction ϕc ≃ 0.84. Experimental data agree with classical viscosity laws of hard spheres suspensions adapted to the 2D geometry, assuming viscous dissipation resulting from the squeeze of the liquid/air interfaces between the particles. Finally, we show that the observed viscous dissipation in particulate films has to be considered to describe the edge velocity during a retraction experiment at large particle coverage.
Pereira, A V; Pereira, S A; Gremião, I D F; Campos, M P; Ferreira, A M R
2012-11-01
This study compared the sensitivity of acetate tape impression and skin squeezing with that of deep skin scraping for the diagnosis of demodicosis in dogs. Demodex canis was detected in 100% of acetate tape impressions obtained after skin squeezing and in 90% of deep skin scrapings. There was a significant difference (P < 0.001) between the techniques in the total number of mites detected. Acetate tape impression with skin squeezing was found to be more sensitive than deep skin scraping and is an alternative diagnostic method for canine demodicosis. © 2012 The Authors. Australian Veterinary Journal © 2012 Australian Veterinary Association.
Symplectic Group Representation of the Two-Mode Squeezing Operator in the Coherent State Basis
Fan, Hong-Yi; Chen, Jun-Hua
2003-11-01
We find that the coherent state projection operator representation of the two-mode squeezing operator constitutes a loyal group representation of symplectic group, which is a remarkable property of the coherent state. As a consequence, the resultant effect of successively applying two-mode squeezing operators are equivalent to a single squeezing in the two-mode Fock space. Generalization of this property to the 2n-mode case is also discussed. The project supported by National Natural Science Foundation of China under Grant No. 10575057
Transparency or spectral narrowing for two-mode squeezing and entanglement
International Nuclear Information System (INIS)
Hu Xiangming; Oh, C. H.
2011-01-01
We analyze the nonadiabatic effects on the propagation of a two-mode squeezed field inside a medium of three-level Λ atoms that display the dark resonance. We identify the different effects for the two-mode quantum properties: (i) unconditional transparency for the sum squeezing and (ii) induced transparency or spectral narrowing for the difference squeezing depending on the relative widths of the initial correlation spectrum to the transparency window. These effects combine to induce transparency or spectrum narrowing for the bipartite entanglement. The potential applications range from quantum information to laser spectroscopy and frequency standards.
Novel polymers as scale inhibitors for squeeze treatments
Energy Technology Data Exchange (ETDEWEB)
Duccini, Y.
1996-12-31
Squeeze treatments are increasingly important to recover oil from offshore platforms. During production deposition occurs and scale inhibitors are widely used. Different chemicals are already used to inhibit several scaling components, including BaSO{sub 4} which appears to be the major problem in wells of the North Sea. Phosphonates, polyacrylates, phosphinocarboxylates and polyvinylsulfonates are the leading products. All of them do not fulfill end users requirements, especially for harsh conditions such as low pHs, high barium and extreme temperatures and pressures. The paper describes new inhibitors both for standard conditions and harsh conditions which are overcoming most of the present drawbacks. In both sets of conditions, the results on performances, stability and absorption-desorption properties are presented. 7 refs., 9 figs., 4 tabs.
Discrete coherent and squeezed states of many-qudit systems
International Nuclear Information System (INIS)
Klimov, Andrei B.; Munoz, Carlos; Sanchez-Soto, Luis L.
2009-01-01
We consider the phase space for n identical qudits (each one of dimension d, with d a primer number) as a grid of d n xd n points and use the finite Galois field GF(d n ) to label the corresponding axes. The associated displacement operators permit to define s-parametrized quasidistributions on this grid, with properties analogous to their continuous counterparts. These displacements allow also for the construction of finite coherent states, once a fiducial state is fixed. We take this reference as one eigenstate of the discrete Fourier transform and study the factorization properties of the resulting coherent states. We extend these ideas to include discrete squeezed states, and show their intriguing relation with entangled states of different qudits.
Two-mode Gaussian density matrices and squeezing of photons
International Nuclear Information System (INIS)
Tucci, R.R.
1992-01-01
In this paper, the authors generalize to 2-mode states the 1-mode state results obtained in a previous paper. The authors study 2-mode Gaussian density matrices. The authors find a linear transformation which maps the two annihilation operators, one for each mode, into two new annihilation operators that are uncorrelated and unsqueezed. This allows the authors to express the density matrix as a product of two 1-mode density matrices. The authors find general conditions under which 2-mode Gaussian density matrices become pure states. Possible pure states include the 2-mode squeezed pure states commonly mentioned in the literature, plus other pure states never mentioned before. The authors discuss the entropy and thermodynamic laws (Second Law, Fundamental Equation, and Gibbs-Duhem Equation) for the 2-mode states being considered
Enhancing photon squeezing one leviton at a time
Ferraro, D.; Ronetti, F.; Rech, J.; Jonckheere, T.; Sassetti, M.; Martin, T.
2018-04-01
A mesoscopic device in the simple tunnel junction or quantum point contact geometry emits microwaves with remarkable quantum properties, when subjected to a sinusoidal drive in the GHz range. In particular, single and two-photon squeezing as well as entanglement in the frequency domain have been reported. By revising the photoassisted noise analysis developed in the framework of electron quantum optics, we present a detailed comparison between the cosine drive case and other experimentally relevant periodic voltages such as rectangular and Lorentzian pulses. We show that the latter drive is the best candidate in order to enhance quantum features and purity of the outgoing single and two-photon states, a noteworthy result in a quantum information perspective.
Applications of quantum electro-optic control and squeezed light
International Nuclear Information System (INIS)
Lam, P.K.
2000-01-01
Full text: The control theory of electronic feedback or feedforward is a topic well understood by many scientists and engineers. With many of the modern equipment relying on automation and robotics, an understanding of this classical control theory is a common requisite for many technologists. In the field of optics, electronic control theory is also commonly used in many situations. From the temperature controlling of laser systems, the auto-alignment of optical elements, to the locking of optical resonators, all make use of electronic control theory in their operations. In this talk, we present the use the control theory in the context of quantum optics. In much the same as its classical counterpart, the 'quantum electro-optic' control loop consists simply of an optical beam splitter, a detector and an electro-optic modulator. This simple system, however, can offer many interesting applications when used in combination with nonclassical states of light. One well-known example of non-classical light is that of the squeezed state of light. A light beam is referred to as being amplitude 'squeezed' when its amplitude has less noise when compared to that of a coherent light state. In fact, the field fluctuation of such light states in some sense lower that the field fluctuation of the photonic vacuum state. Yet another interesting non-classical light state is the so-called 'Einstein-Podolsky-Rosen' entangled pair. This consists of two beams of light, each of which has properties that are highly dependent on each other. Using both the quantum electro-optic control loops and these light states, we demonstrate schemes which allow us to perform noiseless optical amplification, quantum non-demolition measurement and quantum teleportation. These schemes may be important building blocks to the realisation of future quantum communications and quantum information networks
Positioning X-Ray Film Inside A Flow Splitter
Darter, Charles; Pierce, Darryl
1990-01-01
Simple and inexpensive tool ensures secure placement for radiographic inspection. Holder places film positively and securely for x-ray inspection inside sections of tube with splitter welds. V-shaped piece of film fits on arms of holder. With arms squeezed together, holder inserted in opening of neck. Arms of holder cut from 0.020-in. (0.51-mm) thick stock of unspecified material.
International Nuclear Information System (INIS)
Ivanov, K.G.; Mikerina, N.V.
1977-01-01
A comparison is made between the hydromagnetic structure of the interplanetary plasma flux from the powerful solar flare occurred on 4.08.1972 and the magnetic storm of 4-5.08.1972. The geomagnetic effects of the head impact layer of the interplanetary flux are being considered. The world-wide disturbances being most intensive in the Polar regions corresponded to the elements of the substructure of the impact layer. These disturbances are interpreted as the superposition of magnetic fields from reconnection currents on the magnetopause and in the neutral layer of the magnetosphere trail. The qualitative description of the effects under investigation has been made on the assumption that the magnetopause is a rotational impact wave
International Nuclear Information System (INIS)
Lyu, L.H.; Kan, J.R.
1989-01-01
Nonlinear one-dimensional constant-profile hydromagnetic wave solutions are obtained in finite-temperature two-fluid collisionless plasmas under adiabatic equation of state. The nonlinear wave solutions can be classified according to the wavelength. The long-wavelength solutions are circularly polarized incompressible oblique Alfven wave trains with wavelength greater than hudreds of ion inertial length. The oblique wave train solutions can explain the high degree of alignment between the local average magnetic field and the wave normal direction observed in the solar wind. The short-wavelength solutions include rarefaction fast solitons, compression slow solitons, Alfven solitons and rotational discontinuities, with wavelength of several tens of ion inertial length, provided that the upstream flow speed is less than the fast-mode speed
Effects of thoracic squeezing on airway secretion removal in mechanically ventilated patients
Directory of Open Access Journals (Sweden)
Farkhondeh Yousefnia-Darzi
2016-01-01
Conclusions: According to the study findings, endotracheal suction with thoracic squeezing on expiration helps airway secretion discharge more than suction alone in patients on mechanical ventilators and can be used as an effective method.
International Nuclear Information System (INIS)
Chung, N. N.; Chew, L. Y.
2007-01-01
We have generalized the two-step approach to the solution of systems of N coupled quantum anharmonic oscillators. By using the squeezed vacuum state of each individual oscillator, we construct the tensor product state, and obtain the optimal squeezed vacuum product state through energy minimization. We then employ this optimal state and its associated bosonic operators to define a basis set to construct the Heisenberg matrix. The diagonalization of the matrix enables us to obtain the energy eigenvalues of the coupled oscillators. In particular, we have applied our formalism to determine the eigenenergies of systems of two coupled quantum anharmonic oscillators perturbed by a general polynomial potential, as well as three and four coupled systems. Furthermore, by performing a first-order perturbation analysis about the optimal squeezed vacuum product state, we have also examined into the squeezing properties of two coupled oscillator systems
The squeezing properties in the Jaynes-Cummings model with arbitrary intensity-dependent coupling
International Nuclear Information System (INIS)
Rhui-Hua, X.; Dun-Huan, L.; Gong-Ou, X.
1996-01-01
It is studied the squeezing properties of the atom and the radiation field in arbitrary intensity-dependent-coupling Jaynes-Cummings model when it is restricted to the following initial condition: the atom in its coherent state and the field in the vacuum state. The influence of virtual-photon processes on the atomic squeezing predicted by the Jaynes-Cummings model (JCM) has been examined. The relationship between the field and atomic squeezing in the resonant multi-photon JCM has been discussed. The symmetry between the field and atomic squeezing (SFAS) has been exposed in the resonant vacuum one-photon JCM, and the influence of non-resonant interaction and virtual-photon processes on the SFAS has also been discussed
Squeezing of a nanomechanical resonator by quantum nondemolition measurement and feedback
Ruskov, Rusko; Schwab, Keith; Korotkov, Alexander N.
2005-06-01
We analyze squeezing of the nanoresonator state produced by periodic measurement of position by a quantum point contact or a single-electron transistor. The mechanism of squeezing is the stroboscopic quantum nondemolition measurement generalized to the case of continuous measurement by a weakly coupled detector. The magnitude of squeezing is calculated for the harmonic and stroboscopic modulations of measurement, taking into account detector efficiency and nanoresonator quality factor. We also analyze the operation of the quantum feedback, which prevents fluctuations of the wave packet center due to measurement back-action. Verification of the squeezed state can be performed in almost the same way as its preparation; a similar procedure can also be used for the force detection with sensitivity beyond the standard quantum limit.
Temperature and Pressure Evolution during Al Alloy Solidification at Different Squeeze Pressures
International Nuclear Information System (INIS)
Li, Junwen; Zhao, Haidong; Chen, Zhenming
2015-01-01
Squeeze casting is an advanced and near net-shape casting process, in which external high pressure is applied to solidifying castings. The castings are characterized with fine grains and good mechanical properties. In this study, a series of experiments were carried out to measure the temperature and pressure histories in cavity of Al-Si-Mg direct squeeze castings with different applied solidification pressures of 0.1, 50, 75, and 100 MPa. The evolution of the measured temperatures and pressures was compared and discussed. The effect of pressure change on formation of shrinkage defects was analyzed. Further the friction between the castings and dies during solidification was calculated. It is shown that the applied squeeze pressure has significant influence on the friction at die and casting interfaces, which affects the pressure evolution and transmission. The results could provide some benchmark data for future thermal-mechanics coupled modeling of squeeze castings. (paper)
Hu, Long; Tao, Guoquan; Liu, Zhenguo; Wang, Yibo; Ya, Jixuan
2018-04-01
The influence of yarn squeezing effect on the geometric morphology and mechanical property of the three dimensional full five directional (3DF5D) braided composites is explored. Spatial path and cross-section shape of the yarns in the braided structure are characterized based on the micro computed tomography (micro CT) scanning images. The yarn distortion due to the squeezing effect is discussed and mathematical morphology of the yarn geometry is established. A new repeated unit cell (RUC) model of 3DF5D braided composites considering yarn squeezing effect is developed. Based on this model, mechanical properties of 3DF5D braided composites are analyzed. Good agreement is obtained between the predicted and experiment results. Moreover, the stress distribution of the new RUC model are compared with original RUC model, showing that the squeezing effect significantly increases the stress concentration level of the axial yarns.
Control of segregation in squeeze cast Al-4.5Cu binary alloy
Energy Technology Data Exchange (ETDEWEB)
Durrant, G. [Oxford Univ. (United Kingdom). Dept. of Materials; Gallerneault, M. [Alcan International Ltd., Kingston, ON (Canada); Cantor, B. [Oxford Univ. (United Kingdom). Dept. of Materials
1997-10-01
The high pressure applied in squeeze casting allows Al alloys of wrought composition to be cast to near net-shape, although their long freezing range leads to the segregation of alloying elements. In this paper we present results on the squeeze casting and gravity casting of a model Al-4.5 wt%Cu alloy. Squeeze cast Al-4.5Cu has a normal segregation pattern with eutectic macrosegregates towards the centre of the billet, whereas gravity cast material has a typical inverse segregation pattern. Normal segregation in squeeze cast Al-4.5Cu is due to large temperature gradients during solidification. Segregation can be minimized by releasing the applied pressure during solidification to allow backflow of the interdendritic fluid, or by the addition of grain refiner to remove the large columnar dendritic growth structure. (orig.)
Optimization of Squeeze Parameters and Modification of AlSi7Mg Alloy
Directory of Open Access Journals (Sweden)
Zyska A.
2013-06-01
Full Text Available The paper present the examination results concerning mechanical properties of castings made of AlSi7MG alloy in correlation both with the most significant squeeze casting parameters and with the modification treatment. Experiments were planned and held according to the 23 factorial design. The regression equations describing the influence of the squeeze pressure, the mould temperature, and the quantity of strontium modifier on the strength and elongation of the examined alloy were obtained. It was found that the main factor controlling the strength increase is the squeeze pressure, while the plasticity (A5 of the alloy is affected most advantageously by modification. The application of modification treatment in squeeze casting technology enables for production of the slab-type castings made of AlSi7Mg alloy exhibiting strength at the level of 230 MPa and elongation exceeding 14%.
Pulsed Traveling-wave Quadrature Squeezing Using Quasi-phase Matched Lithium Niobate Crystals
Chen, Chao-Hsiang
Interests in generating higher quantum noise squeezing in order to develop methods to enhance optical measurement below the shot-noise limit in various applications has grown in recent years. The noise suppression from squeezing can improve the SNR in coherent optical systems when the returning signal power is weak, such as optical coherence tomography, LADAR, confocal microscopy and low-light coherent imaging. Unlike the generation of squeezing with a continuous wave, which is currently developed mainly for gravitational wave detection in LIGO project, the study of pulsed-traveling waves is focused on industrial, medical and other commercial interests. This dissertation presents the experimental results of pulsed traveling wave squeezing. The intention of the study is to explore the possibility of using quasi-phase matched crystals to generate the highest possible degree of quadrature squeezing. In order to achieve this goal, efforts to test the various effects from spatial Gaussian modes and relative beam waist placement for the second-harmonic pump were carried out in order to further the understanding of limiting factors to pulsed traveling wave squeezing. 20mm and 30mm-long periodically poled lithium noibate (PPLN) crystals were used in the experiment to generate a squeezed vacuum state. A maximum of 4.2+/-0.2dB quadrature squeezing has been observed, and the measured anti-squeezing exceeds 20dB.The phase sensitive amplification (PSA) gain and de-gain performance were also measured to compare the results of measured squeezing. The PPLN crystals can produce high conversion efficiency of second-harmonic generation (SHG) without a cavity. When a long PPLN crystal is used in a squeezer, the beam propagation in the nonlinear medium does not follow the characteristics in thin crystals. Instead, it is operated under the long-crystal criteria, which the crystal length is multiple times longer than the Rayleigh range of the injected beam i n the crystals. Quasi
Non-zero temperature two-mode squeezing for time-dependent two-level systems
International Nuclear Information System (INIS)
Aliaga, J.; Gruver, J.L.; Proto, A.N.; Cerdeira, H.A.
1994-01-01
A Maximum Entropy Principle density matrix method, valid for systems with temperature different from zero, is presented making it possible two-mode squeezed states in two-level systems with relevant operators and Hamiltonian connected with O(3,2). A method which allows one to relate the appearance of squeezing to the relevant operators, included in order to define the density matrix of the system is given. (author). 14 refs, 1 fig
Bright squeezed vacuum in a nonlinear interferometer: frequency/temporal Schmidt-mode description
Sharapova, P. R.; Tikhonova, O. V.; Lemieux, S.; Boyd, R. W.; Chekhova, M. V.
2018-01-01
Control over the spectral properties of the bright squeezed vacuum (BSV), a highly multimode non-classical macroscopic state of light that can be generated through high-gain parametric down conversion, is crucial for many applications. In particular, in several recent experiments BSV is generated in a strongly pumped SU(1,1) interferometer to achieve phase supersensitivity, perform broadband homodyne detection, or tailor the frequency spectrum of squeezed light. In this work, we present an an...
Free-Space Squeezing Assists Perfectly Matched Layers in Simulations on a Tight Domain
DEFF Research Database (Denmark)
Shyroki, Dzmitry; Ivinskaya, Aliaksandra; Lavrinenko, Andrei
2010-01-01
outside the object, as in simulations of eigenmodes or scattering at a wavelength comparable to or larger than the object itself. Here, we show how, in addition to applying the perfectly matched layers (PMLs), outer free space can be squeezed to avoid cutting the evanescent field tails by the PMLs...... or computational domain borders. Adding the squeeze-transform layers to the standard PMLs requires no changes to the finite-difference algorithms....
Section thickness-dependent tensile properties of squeeze cast magnesium alloy AM60
Directory of Open Access Journals (Sweden)
Xuezhi Zhang
2012-05-01
Full Text Available The development of alternative casting processes is essential for the high demand of light weight magnesium components to be used in the automotive industry, which often contain different section thicknesses. Squeeze casting with its inherent advantages has been approved for the capability of minimizing the gas porosity in magnesium alloys. For advanced engineering design of light magnesium automotive applications, it is critical to understand the effect of section thickness on mechanical properties of squeeze cast magnesium alloys. In this study, magnesium alloy AM60 with different section thicknesses of 6, 10 and 20 mm squeeze cast under an applied pressure of 30 MPa was investigated. The prepared squeeze cast AM60 specimens were tensile tested at room termperature. The results indicate that the mechanical properties including yield strength (YS, ultimate tensile strength (UTS and elongation (A decrease with an increase in section thickness of squeeze cast AM60. The microstructure analysis shows that the improvement in the tensile behavior of squeeze cast AM60 is primarily attributed to the low-gas porosity level and fine grain strucuture which result from the variation of cooling rate of different section thickness. The numerical simulation (Magmasoft? was employed to determine the solidification rates of each step, and the simulated results show that the solidification rate of the alloy decreases with an increase in the section thickness. The computed solidification rates support the experimental observation on grain structural development.
Study on fluidity of squeeze cast AZ91D magnesium alloy with different wall thicknesses
Directory of Open Access Journals (Sweden)
Chen Yun
2014-03-01
Full Text Available Rectangular cross-section specimens with different section thicknesses were prepared to study the influences of pouring temperature, mould temperature and squeeze velocity on the fluidity of squeeze cast AZ91D magnesium alloy by means of orthogonal test design method. The results show that pouring temperature, mould temperature and squeeze velocity can significantly affect the fluidity of magnesium alloy specimens with wall thickness no more than 4 mm, and the pouring temperature is the most influential factor on the fluidity of specimens with wall thickness of 1, 2 and 3 mm, while mould temperature is the one for specimens with wall thickness of 4 mm. Increasing pouring temperature between 700 °C and 750 °C is beneficial to the fluidity of AZ91D magnesium alloy, and increasing mould temperature significantly enhances the filling ability of thick (3 and 4 mm section castings. The fluidity of squeeze cast magnesium alloy increases with the increase of wall thickness. It is not recommended to produce magnesium alloy casting with wall thickness of smaller than 3 mm by squeeze cast process due to the poor fluidity. The software DPS was used to generate the regression model, and linear regression equations of the fluidity of squeeze cast AZ91D with different wall thicknesses are obtained using the test results.
Improved spin squeezing of an atomic ensemble through internal state control
Hemmer, Daniel; Montano, Enrique; Deutsch, Ivan; Jessen, Poul
2016-05-01
Squeezing of collective atomic spins is typically generated by quantum backaction from a QND measurement of the relevant spin component. In this scenario the degree of squeezing is determined by the measurement resolution relative to the quantum projection noise (QPN) of a spin coherent state (SCS). Greater squeezing can be achieved through optimization of the 3D geometry of probe and atom cloud, or by placing the atoms in an optical cavity. We explore here a complementary strategy that relies on quantum control of the large internal spin available in alkali atoms such as Cs. Using a combination of rf and uw magnetic fields, we coherently map the internal spins in our ensemble from the SCS (| f = 4, m = 4>) to a ``cat'' state which is an equal superposition of | f = 4, m = 4>and | f = 4, m = -4>. This increases QPN by a factor of 2 f = 8 relative to the SCS, and therefore the amount of backaction and spin-spin entanglement produced by our QND measurement. In a final step, squeezing generated in the cat state basis can be mapped back to the SCS basis, where it corresponds to increased squeezing of the physical spin. Our experiments suggest that up to 8dB of metrologically useful squeezing can be generated in this way, compared to ~ 3 dB in an otherwise identical experiment starting from a SCS.
Is the price squeeze doctrine still viable in fully-regulated energy markets?
International Nuclear Information System (INIS)
Spiwak, L.J.
1993-01-01
Simply stated, a price squeeze occurs when a firm with monopoly power on the primary, or wholesale, level engages in a prolonged price increase that drives competitors out of the secondary, or retail level, and thereby extends its monopoly power to the secondary market. A price squeeze will not be found, however, for any short-term exercise in market power. Rather, because anticompetitive effects of a price squeeze are indirect, the price squeeze must last long enough and be severe enough to produce effects on actual or potential competition in the secondary market. In regulated electric industries, a price squeeze claim usually arises from the complex relationship between the supplier, the wholesale customer, the retail customer, and the federal and state regulators. The supplier sells electric power to both wholesale and retail customers. Wholesale transactions are regulated by federal regulators, and retail transactions are regulated at the state level. The wholesale customers in turn sell power to their retail customers. Over the last several years, there have been substantial developments in the application of the price squeeze doctrine to fully-regulated electric utilities. This article will examine the current developments in this area, and attempt to highlight the burdens potential litigants, both plaintiffs and defendants, must overcome to succeed
Output field-quadrature measurements and squeezing in ultrastrong cavity-QED
Stassi, Roberto; Savasta, Salvatore; Garziano, Luigi; Spagnolo, Bernardo; Nori, Franco
2016-12-01
We study the squeezing of output quadratures of an electro-magnetic field escaping from a resonator coupled to a general quantum system with arbitrary interaction strengths. The generalized theoretical analysis of output squeezing proposed here is valid for all the interaction regimes of cavity-quantum electrodynamics: from the weak to the strong, ultrastrong, and deep coupling regimes. For coupling rates comparable or larger then the cavity resonance frequency, the standard input-output theory for optical cavities fails to calculate the variance of output field-quadratures and predicts a non-negligible amount of output squeezing, even if the system is in its ground state. Here we show that, for arbitrary interaction strength and for general cavity-embedded quantum systems, no squeezing can be found in the output-field quadratures if the system is in its ground state. We also apply the proposed theoretical approach to study the output squeezing produced by: (i) an artificial two-level atom embedded in a coherently-excited cavity; and (ii) a cascade-type three-level system interacting with a cavity field mode. In the latter case the output squeezing arises from the virtual photons of the atom-cavity dressed states. This work extends the possibility of predicting and analyzing the results of continuous-variable optical quantum-state tomography when optical resonators interact very strongly with other quantum systems.
Fidelity of Quantum Teleportation for Single-Mode Squeezed State Light
Institute of Scientific and Technical Information of China (English)
ZHANG Jun-Xiang; XIE Chang-De; PENG Kun-Chi
2005-01-01
@@ The fidelity of quantum teleportation of a single-mode squeezed state of light is calculated based on the general theory of quantum-mechanical measurement in the Schrodinger picture. It is shown that the criterion for the nonclassical state teleportation is different from that for coherent state. F = 1/2 is no longer the rigorous boundary between classical and quantum teleportation for a squeezed state of light. When the quantum entanglement of an Einstein-Podolsky-Rosen (EPR) beam used for teleportation and the parameters of the system are given,the fidelity depends on the squeezing of the input squeezed state. The higher the squeezing is, the smaller the fidelity is, and the lower the classical limitation of fidelity is. The dependence of the optimum gain for teleporting a squeezed vacuum state upon the EPR entanglement is also calculated. The results obtained provide important references for designing experimental systems of teleporting a non-classical state and judging the quality of the teleported quantum state.
Collapse–revival of squeezing of two atoms in dissipative cavities
International Nuclear Information System (INIS)
Zou Hong-Mei; Fang Mao-Fa
2016-01-01
Based on the time-convolutionless master-equation approach, we investigate the squeezing dynamics of two atoms in dissipative cavities. We find that the atomic squeezing is related to initial atomic states, atom–cavity couplings, non-Markovian effects and resonant frequencies of an atom and its cavity. The results show that a collapse–revival phenomenon will occur in the atomic squeezing and this process is accompanied by the buildup and decay of entanglement between two atoms. Enhancing the atom–cavity coupling can increase the frequency of the collapse–revival of the atomic squeezing. The stronger the non-Markovian effect is, the more obvious the collapse–revival phenomenon is. In particular, if the atom–cavity coupling or the non-Markovian effect is very strong, the atomic squeezing will tend to a stably periodic oscillation in a long time. The oscillatory frequency of the atomic squeezing is dependent on the resonant frequency of the atom and its cavity. (paper)
Internal Spin Control, Squeezing and Decoherence in Ensembles of Alkali Atomic Spins
Norris, Leigh Morgan
Large atomic ensembles interacting with light are one of the most promising platforms for quantum information processing. In the past decade, novel applications for these systems have emerged in quantum communication, quantum computing, and metrology. Essential to all of these applications is the controllability of the atomic ensemble, which is facilitated by a strong coupling between the atoms and light. Non-classical spin squeezed states are a crucial step in attaining greater ensemble control. The degree of entanglement present in these states, furthermore, serves as a benchmark for the strength of the atom-light interaction. Outside the broader context of quantum information processing with atomic ensembles, spin squeezed states have applications in metrology, where their quantum correlations can be harnessed to improve the precision of magnetometers and atomic clocks. This dissertation focuses upon the production of spin squeezed states in large ensembles of cold trapped alkali atoms interacting with optical fields. While most treatments of spin squeezing consider only the case in which the ensemble is composed of two level systems or qubits, we utilize the entire ground manifold of an alkali atom with hyperfine spin f greater than or equal to 1/2, a qudit. Spin squeezing requires non-classical correlations between the constituent atomic spins, which are generated through the atoms' collective coupling to the light. Either through measurement or multiple interactions with the atoms, the light mediates an entangling interaction that produces quantum correlations. Because the spin squeezing treated in this dissertation ultimately originates from the coupling between the light and atoms, conventional approaches of improving this squeezing have focused on increasing the optical density of the ensemble. The greater number of internal degrees of freedom and the controllability of the spin-f ground hyperfine manifold enable novel methods of enhancing squeezing. In
Applying squeezing technique to clay-rocks: lessons learned from ten years experiments at Mont Terri
International Nuclear Information System (INIS)
Fernandez, A. M.; Melon, A.; Sanchez-Ledesma, D.M.; Tournassat, C.; Gaucher, E.; Astudillo, J.; Vinsot, A.
2012-01-01
Document available in extended abstract form only. Argillaceous formations of low permeability are considered in several countries as potential host rocks for the disposal of high level radioactive wastes (HLRW). In order to determine their suitability for waste disposal, evaluations of the hydro-geochemistry and transport mechanisms from such geologic formations to the biosphere must be undertaken. The migration of radionuclides through the geosphere will occur predominantly in the aqueous phase, and hence the pore water chemistry plays an important role in determining ion diffusion characteristics in argillaceous formations. Consequently, a great effort has been made to characterise the pore water chemistry in clay-rocks formations. In the last 10 years various techniques were developed for determining pore water composition of clay-rocks including both direct and indirect methods: 1) In situ pore water sampling (water and gas) from sealed boreholes (Pearson et al., 2003; Vinsot et al. 2008); 2) Laboratory pore water sampling from unaltered core samples by the squeezing technique at high pressures (Fernandez et al., 2009); and 3) Characterization of the water chemistry by geochemical modelling (Gaucher et al. 2009). Pore water chemistry in clay-rocks and extraction techniques were documented and reviewed in different studies (Sacchi et al., 2001). Recovering pristine pore water from low permeable and low water content systems is very difficult and sometimes impossible. Besides, uncertainties are associated to each method used for the pore water characterization. In this paper, a review about the high pressure squeezing technique applied to indurate clay-rocks was performed. For this purpose, the experimental work on Opalinus Clay at the Mont Terri Research Laboratory during the last ten years was evaluated. A complete discussion was made about different issues such as: a) why is necessary to obtain the pore water by squeezing in the context of radioactive waste
Zhang, Yu-Yu
2016-01-01
Generalized squeezing rotating-wave approximation (GSRWA) is proposed by employing both the displacement and the squeezing transformations. A solvable Hamiltonian is reformulated in the same form as the ordinary RWA ones. For a qubit coupled to oscillators experiment, a well-defined Schr\\"{o}dinger-cat-like entangled state is given by the displaced-squeezed oscillator state instead of the original displaced state. For the isotropic Rabi case, the mean photon number and the ground-state energy...
Zhang, Yu-Yu; Chen, Xiang-You
2017-01-01
A novel, unexplored nonperturbative deep-strong coupling (npDSC) achieved in superconducting circuits has been studied in the anisotropic Rabi model by the generalized squeezing rotating-wave approximation (GSRWA). Energy levels are evaluated analytically from the reformulated Hamiltonian and agree well with numerical ones under a wide range of coupling strength. Such improvement ascribes to deformation effects in the displaced-squeezed state presented by the squeezed momentum variance, which...
A Method for Seawater Desalination via Squeezing Ionic Hydrogels.
Yu, Chi; Wang, Yanhong; Lang, Xuemei; Fan, Shuanshi
2016-12-06
In this study, mechanical force applied to squeeze poly(sodium acrylate-co-2-hydroxyethyl methacrylate) hydrogels that contained seawater in order to obtain fresh water. By incorporating ionic monomer sodium acrylate (SA) into hydrogels, the salt rejection was significantly enhanced from 27.62% to 64.57% (feed concentration 35.00g/L NaCl solution). As SA's concentration continuously increased, salt rejection declined due to the change in hydrogel's matrix structure. Therefore, water recovery raised as the current swelling degree increased. We also measured pore size distribution by applying mercury intrusion porosimetry on each hydrogel sample in the interest of finding out whether the sample SA5/HEMA15 owned multi pore structure, since the result could be good for the desalination performance. After 4 times reused, the hydrogel remained good desalination performance. Although compared to reverse osmosis (RO) and multistage flash distillation (MSF) & multiple effect distillation (MED) the salt rejection of this hydrogel (roughly 64%) seemed low, the hydrogels can be used for forward osmosis and reverse osmosis, as pretreatment of seawater to reduce the energy consumption for the downstream.
Squeeze flow between a sphere and a textured wall
Energy Technology Data Exchange (ETDEWEB)
Chastel, T.; Mongruel, A., E-mail: anne.mongruel@upmc.fr [Physique et Mécanique des Milieux Hétérogènes, UMR 7636 CNRS–ESPCI, Université Pierre et Marie Curie–Université Paris-Diderot, 10 rue Vauquelin, 75231 Paris Cedex 05 (France)
2016-02-15
The motion of a millimetric sphere, translating in a viscous fluid towards a wettable textured wall, is investigated experimentally. The textures consist of square arrays of cylindrical or square micro-pillars, the height, width, and spacing of which are varied, keeping the periodicity small compared to the sphere radius. An interferometric device is used to measure the sphere vertical displacement, for distances between the sphere and the base of the pillars smaller than 0.1 sphere radius, and with a resolution of 200 nm. At a given distance from the top of the pillars, the sphere velocity is found to be significantly larger than the corresponding velocity for a smooth solid wall. A squeeze flow model of two adjacent fluid layers is developed in the lubrication approximation, one fluid layer having an effective viscosity that reflects the viscous dissipation through the array of pillars. The pressure field in the gap between the sphere and the textured surface is then used to obtain the drag force on the sphere and hence its velocity. Adjustment of the model to the velocity measurements yields the effective viscosity for a given texture. Finally, a correlation between the effective viscosity and the geometry of the pillar array is proposed.
Atomic squeezed states on an atom-chip
International Nuclear Information System (INIS)
Maussang, Kenneth
2010-01-01
In this thesis, we describe the construction of an experiment, allowing to produce 87 Rb Bose-Einstein condensates on an atom chip, and then split them in a double well potential. An accurate imaging system has been developed, in order to be able to measure the absolute value of the populations of the double well within a very low noise level, almost limited by the optical shot noise. We measure atom number statistics after splitting, and directly observe number squeezed states, down to -4.9 dB at low temperatures, compared to a classical gas, of independent particles. The dependence in temperature of fluctuations has been also studied. For a thermal gas, Poissonian fluctuations are given by the probability distribution of the macroscopic configurations with a given atom number difference. In the degenerate regime, the entropy effect which favors small number differences vanishes, leading to super-Poissonian fluctuations, to more than +3.8 dB close to transition temperature. At low temperatures, the interaction energy cost associated with number fluctuations exceeds the available thermal energy, leading to sub-Poissonian fluctuations. Those two behaviours have been theoretically explained, both with a simple analytical model and a numerical one. We also measured the evolution of the relative phase between the two clouds, and its collapse due to interactions, allowing us to claim that this splitter is a coherent one. (author)
Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence
Institute of Scientific and Technical Information of China (English)
Zhang Jian; Shao Bin; Zou Jian
2009-01-01
In this paper,we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling.We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially.The effects of the field squeezing factor,the two-level atomic transition frequency,the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed.Without intrinsic decoherence,the increase of field squeezing factor can break the entropy squeezing.The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing.The influence of the second field frequency is complicated.With the intrinsic decoherence taken into consideration,the results show that the stronger the intrinsic decoherence is,the more quickly the entropy squeezing will disappear.The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing.
Li, Yuan; Zhou, Yusheng; Wang, Yong; Ling, Qiang; Chen, Bing; Dou, Yan; Zhang, Wei; Gao, Weiqing; Guo, Zhiqiang; Zhang, Junxiang
2018-03-01
We theoretically study the squeezed probe light passing through a double electromagnetically induced transparency (DEIT) system, in which a microwave field and two coupling lights drive a loop transition. It is shown that the output squeezing can be maintained in both two transparency windows of DEIT, and it can also be manipulated by the relative phase of the three driving fields. The influence of the intensity of applied fields and the optical depth of atoms on the squeezing is also investigated. This study offers possibilities to manipulate the squeezing propagation in atomic media by the phase of electromagnetic fields.
Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence
International Nuclear Information System (INIS)
Jian, Zhang; Bin, Shao; Jian, Zou
2009-01-01
In this paper, we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling. We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially. The effects of the field squeezing factor, the two-level atomic transition frequency, the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed. Without intrinsic decoherence, the increase of field squeezing factor can break the entropy squeezing. The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing. The influence of the second field frequency is complicated. With the intrinsic decoherence taken into consideration, the results show that the stronger the intrinsic decoherence is, the more quickly the entropy squeezing will disappear. The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing. (classical areas of phenomenology)
Squeezed light for the interferometric detection of high-frequency gravitational waves
Schnabel, R.; Harms, J.; Strain, K. A.; Danzmann, K.
2004-03-01
The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 106dB/20dB ap 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 × 10-23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity.
Squeezed light for the interferometric detection of high-frequency gravitational waves
International Nuclear Information System (INIS)
Schnabel, R; Harms, J; Strain, K A; Danzmann, K
2004-01-01
The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 10 6dB/20dB ∼ 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 x 10 -23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity
dell'Anno, Fabio; de Siena, Silvio; Illuminati, Fabrizio
2004-03-01
Extending the scheme developed for a single mode of the electromagnetic field in the preceding paper [F. Dell’Anno, S. De Siena, and F. Illuminati, Phys. Rev. A 69, 033812 (2004)], we introduce two-mode nonlinear canonical transformations depending on two heterodyne mixing angles. They are defined in terms of Hermitian nonlinear functions that realize heterodyne superpositions of conjugate quadratures of bipartite systems. The canonical transformations diagonalize a class of Hamiltonians describing nondegenerate and degenerate multiphoton processes. We determine the coherent states associated with the canonical transformations, which generalize the nondegenerate two-photon squeezed states. Such heterodyne multiphoton squeezed states are defined as the simultaneous eigenstates of the transformed, coupled annihilation operators. They are generated by nonlinear unitary evolutions acting on two-mode squeezed states. They are non-Gaussian, highly nonclassical, entangled states. For a quadratic nonlinearity the heterodyne multiphoton squeezed states define two-mode cubic phase states. The statistical properties of these states can be widely adjusted by tuning the heterodyne mixing angles, the phases of the nonlinear couplings, as well as the strength of the nonlinearity. For quadratic nonlinearity, we study the higher-order contributions to the susceptibility in nonlinear media and we suggest possible experimental realizations of multiphoton conversion processes generating the cubic-phase heterodyne squeezed states.
Energy Technology Data Exchange (ETDEWEB)
Yan, Yan [Department of Physics, Huazhong Normal University, Wuhan (China); School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Zhu, Jia-pei [Department of Physics, Honghe University, Mengzi (China); Zhao, Shao-ming; Li, Gao-xiang [Department of Physics, Huazhong Normal University, Wuhan (China)
2015-01-01
The quadrature squeezing of a mechanical resonator (MR) coupled with two quantum dots (QDs) through the electromechanical coupling, where the QDs are driven by a strong and two weak laser fields is investigated. By tuning the gate voltage, the electron can be trapped in a quantum pure state. Under certain conditions, the discrepancies between the transition frequency and that of two weak fields are compensated by the phonons induced by the electromechanical coupling of the MR with QDs. In this case, some dissipative processes occur resonantly. The phonons created and (or) annihilated in these dissipative processes are correlated thus leading to the quadrature squeezing of the MR. A squeezed vacuum reservoir for the MR is built up. By tuning the gate voltage to control the energy structure of the QDs, the present squeezing scheme has strong resistance against the dephasing processes of the QDs in low temperature limit. The role of the temperature of the phonon reservoir is to damage squeezing of the MR. (copyright 2014 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
International Nuclear Information System (INIS)
Dell'Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio
2004-01-01
Extending the scheme developed for a single mode of the electromagnetic field in the preceding paper [F. Dell'Anno, S. De Siena, and F. Illuminati, Phys. Rev. A 69, 033812 (2004)], we introduce two-mode nonlinear canonical transformations depending on two heterodyne mixing angles. They are defined in terms of Hermitian nonlinear functions that realize heterodyne superpositions of conjugate quadratures of bipartite systems. The canonical transformations diagonalize a class of Hamiltonians describing nondegenerate and degenerate multiphoton processes. We determine the coherent states associated with the canonical transformations, which generalize the nondegenerate two-photon squeezed states. Such heterodyne multiphoton squeezed states are defined as the simultaneous eigenstates of the transformed, coupled annihilation operators. They are generated by nonlinear unitary evolutions acting on two-mode squeezed states. They are non-Gaussian, highly nonclassical, entangled states. For a quadratic nonlinearity the heterodyne multiphoton squeezed states define two-mode cubic phase states. The statistical properties of these states can be widely adjusted by tuning the heterodyne mixing angles, the phases of the nonlinear couplings, as well as the strength of the nonlinearity. For quadratic nonlinearity, we study the higher-order contributions to the susceptibility in nonlinear media and we suggest possible experimental realizations of multiphoton conversion processes generating the cubic-phase heterodyne squeezed states
The EUVE Mission at UCB: Squeezing More From Less
Stroozas, B. A.; Cullison, J. L.; McDonald, K. E.; Nevitt, R.; Malina, R. F.
2000-05-01
With 8 years on orbit, and over three years in an outsourced mode at U.C. Berkeley (UCB), NASA's Extreme Ultraviolet Explorer (EUVE) continues to be a highly mature and productive scientific mission. The EUVE satellite is extremely stable and exhibits little degradation in its original scientific capabilities, and science data return continues to be at the >99% level. The Project's very small, dedicated, innovative, and relatively cheap ( \\$1 million/year) support team at UCB continues to validate the success of NASA's outsourcing "experiment" while providing a very high science-per-dollar return on NASA's investment with no significant additional risk to the flight systems. The EUVE mission still has much more to offer in terms of important and exciting scientific discoveries as well as mission operations innovations. To highlight this belief the EUVE team at UCB continues to find creative ways to do more with less -- to squeeze the maximum out of available funds -- in NASA's "cheaper, better, faster" environment. This paper provides an overview of the EUVE mission's past, current, and potential future efforts toward automating and integrating its multi-functional data processing systems in proposal management, observation planning, mission operations and engineering, and the processing, archival, and delivery of raw telemetry and science data products. The paper will also discuss the creative allocation of the Project's few remaining personnel resources who support both core mission functions and new innovations, while at the same time minimizing overall risk and stretching the available budget. This work is funded through NASA/UCB Cooperative Agreement NCC5-138.
Electroviscous dissipation in aqueous electrolyte films with overlapping electric double layers
Liu, Fei; Klaassen, Aram Harold; Zhao, Cunlu; Mugele, Friedrich Gunther; van den Ende, Henricus T.M.
2018-01-01
We use dynamic atomic force microscopy (AFM) to investigate the forces involved in squeezing out thin films of aqueous electrolyte between an AFM tip and silica substrates at variable pH and salt concentration. From amplitude and phase of the AFM signal we determine both conservative and dissipative
Evolution of the squeezing-enhanced vacuum state in the amplitude dissipative channel
Ren, Gang; Du, Jian-ming; Zhang, Wen-hai
2018-05-01
We study the evolution of the squeezing-enhanced vacuum state (SEVS) in the amplitude dissipative channel by using the two-mode entangled state in the Fock space and Kraus operator. The explicit formulation of the output state is also given. It is found that the output state does not exhibit sub-Poissonian behavior for the nonnegative value of the Mandel's Q-parameters in a wide range of values of squeezing parameter and dissipation factor. It is interesting to see that second-order correlation function is independent of the dissipation factor. However, the photon-number distribution of the output quantum state shows remarkable oscillations with respect to the dissipation factor. The shape of Wigner function and the degree of squeezing show that the initial SEVS is dissipated by the amplitude dissipative channel.
Squeeze behavior of magnetorheological fluids under constant volume and uniform magnetic field
International Nuclear Information System (INIS)
Guo, Chaoyang; Gong, Xinglong; Xuan, Shouhu; Yan, Qifan; Ruan, Xiaohui
2013-01-01
In this work the experimental investigation of magnetorheological fluids in squeeze mode has been carried out under constant volume with a self-developed device. The magnetorheological fluids were forced to move in all directions in a horizontal plane as the two flat surfaces came together. A pair of Helmholtz coils was used to generate a uniform magnetic field in the compression gap. The normal forces within the gap were systematically studied for different magnetic field, squeeze velocity, particle concentration, viscosity of carrier fluid and initial gap distance. Two regions of behavior were obtained from the normal force versus gap distance curve: elastic deformation and plastic flow. A power law fitting was appropriate for the relation between the normal force and the gap in the plastic flow. The index of the power law was smaller than that predicted by the continuum theory, possibly due to the squeeze strengthening effect and the sealing effect. (paper)
Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha
2018-03-01
A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method). The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics.
Squeezed bispectrum in the δ N formalism: local observer effect in field space
Energy Technology Data Exchange (ETDEWEB)
Tada, Yuichiro [Kavli Institute for the Physics and Mathematics of the Universe (WPI), UTIAS, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Vennin, Vincent, E-mail: yuichiro.tada@ipmu.jp, E-mail: vincent.vennin@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom)
2017-02-01
The prospects of future galaxy surveys for non-Gaussianity measurements call for the development of robust techniques for computing the bispectrum of primordial cosmological perturbations. In this paper, we propose a novel approach to the calculation of the squeezed bispectrum in multiple-field inflation. With use of the δ N formalism, our framework sheds new light on the recently pointed out difference between the squeezed bispectrum for global observers and that for local observers, while allowing one to calculate both. For local observers in particular, the squeezed bispectrum is found to vanish in single-field inflation. Furthermore, our framework allows one to go beyond the near-equilateral ('small hierarchy') limit, and to automatically include intrinsic non-Gaussianities that do not need to be calculated separately. The explicit computational programme of our method is given and illustrated with a few examples.
Low-noise, transformer-coupled resonant photodetector for squeezed state generation.
Chen, Chaoyong; Shi, Shaoping; Zheng, Yaohui
2017-10-01
In an actual setup of squeezed state generation, the stability of a squeezing factor is mainly limited by the performance of the servo-control system, which is mainly influenced by the shot noise and gain of a photodetector. We present a unique transformer-coupled LC resonant amplifier as a photodetector circuit to reduce the electronic noise and increase the gain of the photodetector. As a result, we obtain a low-noise, high gain photodetector with the gain of more than 1.8×10 5 V/A, and the input current noise of less than 4.7 pA/Hz. By adjusting the parameters of the transformer, the quality factor Q of the resonant circuit is close to 100 in the frequency range of more than 100 MHz, which meets the requirement for weak power detection in the application of squeezed state generation.
The Effect of Spin Squeezing on the Entanglement Entropy of Kicked Tops
Directory of Open Access Journals (Sweden)
Ernest Teng Siang Ong
2016-04-01
Full Text Available In this paper, we investigate the effects of spin squeezing on two-coupled quantum kicked tops, which have been previously shown to exhibit a quantum signature of chaos in terms of entanglement dynamics. Our results show that initial spin squeezing can lead to an enhancement in both the entanglement rate and the asymptotic entanglement for kicked tops when the initial state resides in the regular islands within a mixed classical phase space. On the other hand, we found a reduction in these two quantities if we were to choose the initial state deep inside the chaotic sea. More importantly, we have uncovered that an application of periodic spin squeezing can yield the maximum attainable entanglement entropy, albeit this is achieved at a reduced entanglement rate.
Entanglement between atomic thermal states and coherent or squeezed photons in a damping cavity
Yadollahi, F.; Safaiee, R.; Golshan, M. M.
2018-02-01
In the present study, the standard Jaynes-Cummings model, in a lossy cavity, is employed to characterize the entanglement between atoms and photons when the former is initially in a thermal state (mixed ensemble) while the latter is described by either coherent or squeezed distributions. The whole system is thus assumed to be in equilibrium with a heat reservoir at a finite temperature T, and the measure of negativity is used to determine the time evolution of atom-photon entanglement. To this end, the master equation for the density matrix, in the secular approximation, is solved and a partial transposition of the result is made. The degree of atom-photon entanglement is then numerically computed, through the negativity, as a function of time and temperature. To justify the behavior of atom-photon entanglement, moreover, we employ the so obtained total density matrix to compute and analyze the time evolution of the initial photonic coherent or squeezed probability distributions and the squeezing parameters. On more practical points, our results demonstrate that as the initial photon mean number increases, the atom-photon entanglement decays at a faster pace for the coherent distribution compared to the squeezed one. Moreover, it is shown that the degree of atom-photon entanglement is much higher and more stable for the squeezed distribution than that for the coherent one. Consequently, we conclude that the time intervals during which the atom-photon entanglement is distillable is longer for the squeezed distribution. It is also illustrated that as the temperature increases the rate of approaching separability is faster for the coherent initial distribution. The novel point of the present report is the calculation of dynamical density matrix (containing all physical information) for the combined system of atom-photon in a lossy cavity, as well as the corresponding negativity, at a finite temperature.
Entropy squeezing of the field interacting with a nearly degenerate V-type three-level atom
Institute of Scientific and Technical Information of China (English)
Zhou Qing-Chun; Zhu Shi-Ning
2005-01-01
The position- and momentum-entopic squeezing properties of the optical field in the system of a nearly degenerate three-level atom interacting with a single-mode field are investigated. Calculation results indicate that when the field is initially in the vacuum state, it may lead to squeezing of the position entropy or the momentum entropy of the field if the atom is prepared properly. The effects of initial atomic state and the splitting of the excited levels of the atom on field entropies are discussed in this case. When the initial field is in a coherent state, we find that position-entropy squeezing of the field is present even if the atom is prepared in the ground state. By comparing the variance squeezing and entropy squeezing of the field we confirm that entropy is more sensitive than variance in measuring quantum fluctuations.
Zhang, Yu-Yu
2016-12-01
Generalized squeezing rotating-wave approximation (GSRWA) is proposed by employing both the displacement and the squeezing transformations. A solvable Hamiltonian is reformulated in the same form as the ordinary RWA ones. For a qubit coupled to oscillators experiment, a well-defined Schrödinger-cat-like entangled state is given by the displaced-squeezed oscillator state instead of the original displaced state. For the isotropic Rabi case, the mean photon number and the ground-state energy are expressed analytically with additional squeezing terms, exhibiting a substantial improvement of the GSRWA. And the ground-state energy in the anisotropic Rabi model confirms the effectiveness of the GSRWA. Due to the squeezing effect, the GSRWA improves the previous methods only with the displacement transformation in a wide range of coupling strengths even for large atom frequency.
The precision and torque production of common hip adductor squeeze tests used in elite football
DEFF Research Database (Denmark)
Light, N; Thorborg, K
2016-01-01
OBJECTIVES: Decreased hip adductor strength is a known risk factor for groin injury in footballers, with clinicians testing adductor strength in various positions and using different protocols. Understanding how reliable and how much torque different adductor squeeze tests produce will facilitate...... choosing the most appropriate method for future testing. In this study, the reliability and torque production of three common adductor squeeze tests were investigated. DESIGN: Test-retest reliability and cross-sectional comparison. METHODS: Twenty elite level footballers (16-33 years) without previous...
SQUEEZING EFFECT OF RAIL LOADED BY SEMI-SLEEPERS HAVING L-SHAPED CROSS-SECTION
Directory of Open Access Journals (Sweden)
V. N. Sukhodoev
2015-01-01
Full Text Available The paper considers a problem on introduction of a conception and regularities of “squeezing effect of a rail loaded non centrally by semi-sleepers having L-shaped cross-section” exemplified by belt-type tramway. Its advantages are ensured by doubled non centrally loaded foundations these are semi-sleepers. Semi-sleeper of L-shape cross-section is a lever of L-shape form, transforming a vertical load into horizontal ones and foundation squeezing. Properties of two semi-sleepers being doubled, orientated to each other and non centrally loaded have been used in order to create a positive effect. A horizontal force creates squeezing and it is revealed as a component of a vertical load during displacements which functionally depend on foundation squeezing. These dependences demonstrate that strength and deformation properties of earth foundation of vertical direction are used for creation of horizontal properties of sleeper vertical shoulder.The paper studies mechanics pertaining to a squeezing effect of a rail loaded by semi-sleepers having L-shaped cross-section. It has been established that the rail squeezing effect results from squeezing process executed in two mutually perpendicular directions (reduction of cross-sectional area by load of a rail wheel with spacers if they are set inside of a sleeper-mechanism on an elastic foundation.Methodology for calculation of parameters on the rail reduction effect is considered as a tool for handling of applied problems on belt-type tramways. Results of the proposed rail reduction effect in problem statement for elastic conditions, with unchanged cross-sectional dimension of a rail line and introduction of correction ratio coefficients due to new initial load data have recommended for practical application as reliable values.The paper has revealed a proportional dependence of the rail reduction effect according to strength on the resultant value of reaction pressure, eccentricity difference of the
Quantum noise on a point charge from electromagnetic squeezed vacuum fluctuations
International Nuclear Information System (INIS)
Wu, Tai-Hung; Hsiang, Jen-Tsung; Lee, Da-Shin
2010-01-01
The effect of quantum noises on a point charge from electromagnetic squeezed vacuum fluctuations is studied. Here a novel reduction phenomenon in velocity dispersion is found in the situation when the particle barely moves. It shows that the velocity dispersion of the charge can be reduced below the value solely given by the normal vacuum states of the electromagnetic fields by using an appropriate choice of the squeeze parameters. This may be viewed as a transient phenomenon. Optimally utilizing this reduction scheme for gravitational wave detection is possible, but challenging.
Quantum noise on a point charge from electromagnetic squeezed vacuum fluctuations
Energy Technology Data Exchange (ETDEWEB)
Wu, Tai-Hung; Hsiang, Jen-Tsung; Lee, Da-Shin [National Dong-Hwa University, Hua-lien, Taiwan (China)
2010-09-15
The effect of quantum noises on a point charge from electromagnetic squeezed vacuum fluctuations is studied. Here a novel reduction phenomenon in velocity dispersion is found in the situation when the particle barely moves. It shows that the velocity dispersion of the charge can be reduced below the value solely given by the normal vacuum states of the electromagnetic fields by using an appropriate choice of the squeeze parameters. This may be viewed as a transient phenomenon. Optimally utilizing this reduction scheme for gravitational wave detection is possible, but challenging.
DEFF Research Database (Denmark)
Møller, Klaus Braagaard; Jørgensen, Thomas Godsk; Dahl, Jens Peder
1996-01-01
For some applications the overall phase of a quantum state is crucial. For the so-called displaced squeezed number state (DSN), which is a generalization of the well-known squeezed coherent state, we obtain the position space representation with the correct overall phase, from the dynamics...... in a harmonic potential. The importance of the overall phase is demonstrated in the context of characteristic or moment generating functions. For two special cases the characteristic function is shown to be computable from the inner product of two different DSNs....
Coastal and Estuarine Mangrove Squeeze in the Mekong and Saigon Delta
Stive, M.
2016-02-01
Both in the Mekong and Saigon deltas coastal squeeze is a frequent and pregnant problem, which leads to amazingly alarmous coastal and estuarine erosion rates. From the landside the squeeze is due to encroaching dike relocations and agri- and aquacultures, from the sea side it is due to decreasing sediment sources and relative sea level rise. These multiple pressures at some locations, certainly away from the sediment sources (like Ca Mau) leads to unprecedentent erosion rates. Managed retreat may be a longer term solution, but this will require a new way of thinking. Sandy and silt nourishment strategies may be an innovative alternative, but will require underbuilding scientific and practical research.
Searching for squeezed particle-antiparticle correlations in high-energy heavy-ion collisions
International Nuclear Information System (INIS)
Padula, Sandra S.; Socolowski, O. Jr.
2010-01-01
Squeezed correlations of particle-antiparticle pairs were predicted to exist if the hadron masses were modified in the hot and dense medium formed in high-energy heavy-ion collisions. Although well-established theoretically, they have not yet been observed experimentally. We suggest here a clear method to search for such a signal by analyzing the squeezed correlation functions in terms of measurable quantities. We illustrate this suggestion for simulated φφ pairs at the Relativistic Heavy Ion Collider (RHIC) energies.
Effect of magnon-phonon interactions on magnon squeezed states in ferromagnets
Mikhail, I. F. I.; Ismail, I. M. M.; Ameen, M.
2018-02-01
The squeezed states of dressed magnons in ferromagnets have been investigated. No effective Debye cutoff frequency has been assumed unlike what has been done hitherto. Instead, the results have been expressed throughout in terms of the reduced temperature. The effect of dressed magnon-phonon interactions on the formulation of these states has been studied. It has been shown that the magnon-phonon interactions play a significant role in determining the squeeze factor and the variation of the dressed magnon effective mass with temperature.
Superposition of number and squeezed states of the quantized light field
International Nuclear Information System (INIS)
De Brito, A.L.; Marques, G.A.; Baseia, B.; Dias, H.
1998-01-01
A recent paper in the literature (Mod. Phys. Lett. B, 9 (1995) 1673) introduced the Intermediate Number Squeezed State (INSS) of the quantized radiation field interpolating between the number state (n) and the squeezed-coherent state (z, α), exhibiting various nonclassical properties. Here, it's introduced an alternative state, interpolating between those limiting states and show that nonclassical effects in this new intermediate state can be greater than those exhibited by the INSS, depending on the values of the interpolating parameters. Although constituting an application of a general approach (Nuovo Cimento D, 18 (1996) 425), it concludes another case in the literature (Phys. Scr., 55 (1997) 179) as a particularisation of this
Squeezed-light generation in a nonlinear planar waveguide with a periodic corrugation
International Nuclear Information System (INIS)
Perina, Jan Jr.; Haderka, Ondrej; Sibilia, Concita; Bertolotti, Mario; Scalora, Michael
2007-01-01
Two-mode nonlinear interaction (second-harmonic and second-subharmonic generation) in a planar waveguide with a small periodic corrugation at the surface is studied. Scattering of the interacting fields on the corrugation leads to constructive interference that enhances the nonlinear process provided that all the interactions are phase matched. Conditions for the overall phase matching are found. Compared with a perfectly quasi-phase-matched waveguide, better values of squeezing as well as higher intensities are reached under these conditions. Procedure for finding optimum values of parameters for squeezed-light generation is described
Managing the spatial properties and photon correlations in squeezed non-classical twisted light
Zakharov, R. V.; Tikhonova, O. V.
2018-05-01
Spatial photon correlations and mode content of the squeezed vacuum light generated in a system of two separated nonlinear crystals is investigated. The contribution of both the polar and azimuthal modes with non-zero orbital angular momentum is analyzed. The control and engineering of the spatial properties and degree of entanglement of the non-classical squeezed light by changing the distance between crystals and pump parameters is demonstrated. Methods for amplification of certain spatial modes and managing the output mode content and intensity profile of quantum twisted light are suggested.
International Nuclear Information System (INIS)
Rahman, M.M.; Al-Lawatia, M.A.; Eltayeb, I.A.; Al-Salti, N.
2012-01-01
Heat transfer characteristics of a two-dimensional steady hydromagnetic slip flow of water based nano-fluids (TiO 2 -water, Al 2 O 3 -water, and Cu-water) over a wedge with convective surface taking into account the effects of heat generation (or absorption) has been investigated numerically. The local similarity solutions are obtained by using very robust computer algebra software MATLAB and presented graphically as well as in a tabular form. The results show that nano-fluid velocity is lower than the velocity of the base fluid and the existence of the nano-fluid leads to the thinning of the hydrodynamic boundary layer. The rate of shear stress is significantly influenced by the surface convection parameter and the slip parameter. It is higher for nano-fluids than the base fluid. The results also show that within the boundary layer the temperature of the nano-fluid is higher than the temperature of the base fluid. The rate of heat transfer is found to increase with the increase of the surface convection and the slip parameters. Addition of nano-particles to the base fluid induces the rate of heat transfer. The rate of heat transfer in the Cu-water nano-fluid is found to be higher than the rate of heat transfer in the TiO 2 -water and Al 2 O 3 -water nano-fluids. (authors)
Influence of squeeze film damping on the higher-order modes of clamped–clamped microbeams
Alcheikh, Nouha; Kosuru, Lakshmoji; Jaber, Nizar; Bellaredj, Mohammed Lamine Faycal; Younis, Mohammad I.
2016-01-01
such resonators in air. Experimental results and finite element model simulations show good agreement for resonance frequency and quality factor for the three studied modes. © 2016 IOP Publishing Ltd.
Garca Fernández, P.; Colet, P.; Toral, R.; San Miguel, M.; Bermejo, F. J.
1991-05-01
The squeezing properties of a model of a degenerate parametric amplifier with absorption losses and an added fourth-order nonlinearity have been analyzed. The approach used consists of obtaining the Langevin equation for the optical field from the Heisenberg equation provided that a linearization procedure is valid. The steady states of the deterministic equations have been obtained and their local stability has been analyzed. The stationary covariance matrix has been calculated below and above threshold. Below threshold, a squeezed vacuum state is obtained and the nonlinear effects in the fluctuations have been taken into account by a Gaussian decoupling. In the case above threshold, a phase-squeezed coherent state is obtained and numerical simulations allowed to compute the time interval, depending on the loss parameter, on which the system jumps from one stable state to the other. Finally, the variances numerically determined have been compared with those obtained from the linearized theory and the limits of validity of the linear theory have been analyzed. It has become clear that the nonlinear contribution may perhaps be profitably used for the construction of above-threshold squeezing devices.
International Nuclear Information System (INIS)
Ghasemi, A; Hooshmandasl, M R; Tavassoly, M K
2011-01-01
In this paper we calculate the position and momentum space information entropies for the quantum states associated with a particular physical system, i.e. the isotonic oscillator Hamiltonian. We present our results for its ground states, as well as for its excited states. We observe that the lower bound of the sum of the position and momentum entropies expressed by the Beckner, Bialynicki-Birula and Mycielski (BBM) inequality is satisfied. Moreover, there exist eigenstates that exhibit squeezing in the position information entropy. In fact, entropy squeezing, which occurs in position, will be compensated for by an increase in momentum entropy, such that the BBM inequality is guaranteed. To complete our study we investigate the amplitude squeezing in x and p-quadratures corresponding to the eigenstates of the isotonic oscillator and show that amplitude squeezing, again in x, will be revealed as expected, while the Heisenberg uncertainty relationship is also satisfied. Finally, our numerical calculations of the entropy densities will be presented graphically.
Ultrafast optical generation of squeezed magnon states and long lifetime coherent LO phonons
Zhao, Jimin
2005-12-01
Ultrafast optical pulses have been used to generate, probe, and control low-energy elementary excitations in crystals. In particular, we report the first experimental demonstration of the generation of quantum squeezed states of magnons (collective spin-wave excitations) in a magnetic material, and new progress in experimental investigation of anharmonic interactions in a semiconductor. The mechanism for the magnon squeezing is two-magnon impulsive stimulated Raman scattering (ISRS). Femtosecond laser pulses have been used to coherently correlate degenerate counter-propagating magnons in the antiferromagnetic insulator MnF2. In the squeezed state, fluctuations of the magnetization of a crystallographic unit cell vary periodically in time and are reduced below that of the ground-state quantum noise. Similar experiments were also performed in another antiferromagnetic insulator, FeF2, for which the squeezing effect is one order of magnitude larger. We have also investigated the anharmonic interaction of the low-frequency E2 phonon in ZnO through ISRS. Temperature dependence of the linewidth and frequency indicates that the two-phonon up-conversion process is the dominant decay channel and isotopic disorder may be the main limit on the lifetime at low temperature. We have observed the longest lifetime of an optical phonon mode in a solid (211 ps at 5 K). And we have found that pump-probe experiments, compared with spontaneous Raman spectroscopy, have extremely high accuracy in determining the frequency of a low-lying excitation.
18 CFR 2.17 - Price discrimination and anticompetitive effect (price squeeze issue).
2010-04-01
... INTERPRETATIONS Statements of General Policy and Interpretations Under the Federal Power Act § 2.17 Price... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Price discrimination and anticompetitive effect (price squeeze issue). 2.17 Section 2.17 Conservation of Power and Water...
Spin Squeezing and Entanglement with Room Temperature Atoms for Quantum Sensing and Communication
DEFF Research Database (Denmark)
Shen, Heng
magnetometer at room temperature is reported. Furthermore, using spin-squeezing of atomic ensemble, the sensitivity of magnetometer is improved. Deterministic continuous variable teleportation between two distant atomic ensembles is demonstrated. The fidelity of teleportating dynamically changing sequence...... of spin states surpasses a classical benchmark, demonstrating the true quantum teleportation....
Directory of Open Access Journals (Sweden)
S. Ahmad
2018-03-01
Full Text Available A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method. The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics. Keywords: Squeezing flow, Sutterby fluid model, Mixed convection, Double stratification, Thermal radiation, Chemical reaction
Combined Ramp and Squeeze to 6.5 TeV in the LHC
Solfaroli Camillocci, Matteo; Tomás, Rogelio; Wenninger, Jorg
2016-01-01
The cycle of the LHC is composed of an energy ramp followed by a betatron squeeze, needed to reduce the beta- star value in the interaction points. Since Run 1, studies have been carried out to investigate the feasibility of combining the two operations, thus considerably reducing the duration of the operational cycle. In Run 2, the LHC is operating at the energy of 6.5 TeV that requires a much longer cycle than that of Run 1. Therefore, the performance gains from a Combined Ramp and Squeeze (CRS) is more interesting. Merging the energy ramp and the betatron squeeze could result in a gain of several minutes for each LHC cycle. With increasing maturity of LHC operation, it is now possible to envisage more complex beam manipulations; this paper describes the first machine experiment with beam, aiming at validating the combination of ramp and squeeze, which was performed in 2015, during a machine development phase. The operation experience with the LHC run at 2.51 TeV, when CRS down to 4 meters was deployed and ...
Squeezing and entanglement in doubly resonant, type II, second-harmonic generation
DEFF Research Database (Denmark)
Andersen, Ulrik Lund; Buchhave, Preben
2003-01-01
We investigate, theoretically, the generation of bright and vacuum-squeezed light as well as entanglement in intracavity, type II, phase-matched second-harmonic generation. The cavity in which the crystal is embedded is resonant at the fundamental frequency but not at the second-harmonic frequenc...
Semiclassical approach to squeezing-like transformations in quantum systems with higher symmetries
International Nuclear Information System (INIS)
Klimov, Andrei B; Dinani, Hossein Tavakoli; De Guise, Hubert
2013-01-01
We provide a coarse but intuitive classification of squeezing in quantum systems with SU(n) symmetries. This classification is based on the non-equivalent paths (classical trajectories) in the corresponding phase-space. The example of SU(3) is studied in details. (paper)
A magneto-rheological fluid mount featuring squeeze mode: analysis and testing
International Nuclear Information System (INIS)
Chen, Peng; Bai, Xian-Xu; Qian, Li-Jun; Choi, Seung-Bok
2016-01-01
This paper presents a mathematical model for a new semi-active vehicle engine mount utilizing magneto-rheological (MR) fluids in squeeze mode (MR mount in short) and validates the model by comparing analysis results with experimental tests. The proposed MR mount is mainly comprised of a frame for installation, a main rubber, a squeeze plate and a bobbin for coil winding. When the magnetic fields on, MR effect occurs in the upper gap between the squeeze plate and the bobbin, and the dynamic stiffness can be controlled by tuning the applied currents. Employing Bingham model and flow properties between parallel plates of MR fluids, a mathematical model for the squeeze type of MR mount is formulated with consideration of the fluid inertia, MR effect and hysteresis property. The field-dependent dynamic stiffness of the MR mount is then analyzed using the established mathematical model. Subsequently, in order to validate the mathematical model, an appropriate size of MR mount is fabricated and tested. The field-dependent force and dynamic stiffness of the proposed MR mount are evaluated and compared between the model and experimental tests in both time and frequency domains to verify the model efficiency. In addition, it is shown that both the damping property and the stiffness property of the proposed MR mount can be simultaneously controlled. (paper)
Spin squeezing and Schrödinger cat generation in atomic samples with Rydberg blockade
DEFF Research Database (Denmark)
Opatrný, Tomáš; Mølmer, Klaus
2012-01-01
A scheme is proposed to prepare squeezed states and Schrödinger-cat-like states of the collective spin degrees of freedom associated with a pair of ground states in an atomic ensemble. The scheme uses an effective Jaynes-Cummings interaction which can be provided by excitation of the atoms...
Exploring Imperfect Squeezing Flow Measurements in a Teflon Geometry for Semisolid Foods
Terpstra, M.E.J.; Janssen, A.M.; Linden, van der E.
2007-01-01
The method of imperfect lubricated squeezing flow in a Teflon¿ geometry has been explored for the characterization of elongational behavior of custard and mayonnaise. Two Newtonian products, one of low (0.07 Pas) and one of high (18 Pas) shear viscosity, were used as references. Measurements of
Squeeze flow of Bingham plastic with stick-slip at the wall
Muravleva, Larisa
2018-03-01
We solve numerically the axisymmetric squeeze flow of a viscoplastic Bingham medium with slip yield boundary condition at the wall. Using the original Bingham model we compute the shape of the yield surface, the velocity, and stress fields employing the augmented Lagrangian methods. We confirm numerically the recently obtained asymptotic solution.
Li, Wei; Jin, Yuanbin; Yu, Xudong; Zhang, Jing
2017-08-01
We experimentally study a protocol of using the broadband high-frequency squeezed vacuum to detect the low-frequency signal. In this scheme, the lower sideband field of the squeezed light carries the low-frequency modulation signal, and the two strong coherent light fields are applied as the bichromatic local oscillator in the homodyne detection to measure the quantum entanglement of the upper and lower sideband for the broadband squeezed light. The power of one of the local oscillators for detecting the upper sideband can be adjusted to optimize the conditional variance in the low-frequency regime by subtracting the photocurrent of the upper sideband field of the squeezed light from that of the lower sideband field. By means of the quantum correlation of the upper and lower sideband for the broadband squeezed light, the low-frequency signal beyond the standard quantum limit is measured. This scheme is appropriate for enhancing the sensitivity of the low-frequency signal by the aid of the broad squeezed light, such as gravitational waves detection, and does not need to directly produce the low-frequency squeezing in an optical parametric process.
Using galaxy pairs to investigate the three-point correlation function in the squeezed limit
Yuan, Sihan; Eisenstein, Daniel J.; Garrison, Lehman H.
2017-11-01
We investigate the three-point correlation function (3PCF) in the squeezed limit by considering galaxy pairs as discrete objects and cross-correlating them with the galaxy field. We develop an efficient algorithm using fast Fourier transforms to compute such cross-correlations and their associated pair-galaxy bias bp, g and the squeezed 3PCF coefficient Qeff. We implement our method using N-body cosmological simulations and a fiducial halo occupation distribution (HOD) and present the results in both the real space and redshift space. In real space, we observe a peak in bp, g and Qeff at pair separation of ∼2 Mpc, attributed to the fact that galaxy pairs at 2 Mpc separation trace the most massive dark matter haloes. We also see strong anisotropy in the bp, g and Qeff signals that track the large-scale filamentary structure. In redshift space, both the 2 Mpc peak and the anisotropy are significantly smeared out along the line of sight due to finger-of-God effect. In both the real space and redshift space, the squeezed 3PCF shows a factor of 2 variation, contradicting the hierarchical ansatz, but offering rich information on the galaxy-halo connection. Thus, we explore the possibility of using the squeezed 3PCF to constrain the HOD. When we compare two simple HOD models that are closely matched in their projected two-point correlation function (2PCF), we do not yet see a strong variation in the 3PCF that is clearly disentangled from variations in the projected 2PCF. Nevertheless, we propose that more complicated HOD models, e.g. those incorporating assembly bias, can break degeneracies in the 2PCF and show a distinguishable squeezed 3PCF signal.
Absorption spectrum of a two-level atom in a bad cavity with injected squeezed vacuum
Zhou, Peng; Swain, S.
1996-02-01
We study the absorption spectrum of a coherently driven two-level atom interacting with a resonant cavity mode which is coupled to a broadband squeezed vacuum through its input-output mirror in the bad cavity limit. We study the modification of the two-photon correlation strength of the injected squeezed vacuum inside the cavity, and show that the equations describing probe absorption in the cavity environment are formally identical to these in free space, but with modified parameters describing the squeezed vacuum. The two photon correlations induced by the squeezed vacuum are always weaker than in free space. We pay particular attention to the spectral behaviour at line centre in the region of intermediate trength driving intensities, where anomalous spectral features such as hole-burning and dispersive profiles are displayed. These unusual spectral features are very sensitive to the squeezing phase and the Rabi frequency of the driving field. We also derive the threshold value of the Rabi frequency which gives rise to the transparency of the probe beam at the driving frequency. When the Rabi frequency is less than the threshold value, the probe beam is absorbed, whilst the probe beam is amplified (without population inversion under certain conditions) when the Rabi frequency is larger than this threshold. The anomalous spectral features all take place in the vicinity of the critical point dividing the different dynamical regimes, probe absorption and amplification, of the atomic radiation. The physical origin of the strong amplification without population inversion, and the feasibility of observing it, are discussed.
Directory of Open Access Journals (Sweden)
S. Vellingiri
2018-01-01
Full Text Available This present investigation deals with squeeze casting process in order to produce a component with good mechanical properties such as micro-hardness(VH, tensile strength(Rm, and density(ρ on LM13 by varying squeeze pressure(P, molten temperature(Tm and die temperature(Td. Taguchi experimental design L9 orthogonal array was used to determine the signal to noise ratio. The results specified that the squeeze pressure and die preheat temperature are the most influencing parameters for mechanical properties improvement. Genetic algorithm (GA has been applied to optimize the casting parameters that simultaneously maximize the responses.
Zhang, Yu-Yu; Chen, Xiang-You
2017-12-01
An unexplored nonperturbative deep strong coupling (npDSC) achieved in superconducting circuits has been studied in the anisotropic Rabi model by the generalized squeezing rotating-wave approximation. Energy levels are evaluated analytically from the reformulated Hamiltonian and agree well with numerical ones in a wide range of coupling strength. Such improvement ascribes to deformation effects in the displaced-squeezed state presented by the squeezed momentum variance, which are omitted in previous displaced states. The atom population dynamics confirms the validity of our approach for the npDSC strength. Our approach offers the possibility to explore interesting phenomena analytically in the npDSC regime in qubit-oscillator experiments.
International Nuclear Information System (INIS)
Senthil, P.; Amirthagadeswaran, K. S.
2012-01-01
This paper reports a research in which an attempt was made to prepare AC2A aluminium alloy castings of a non symmetrical component through squeeze casting process. The primary objective was to investigate the influence of process parameters on mechanical properties of the castings. Experiments were conducted based on orthogonal array suggested in Taguchi's offline quality control concept. The experimental results showed that squeeze pressure, die preheating temperature and compression holding time were the parameters making significant improvement in mechanical properties. The optimal squeeze casting condition was found and mathematical models were also developed for the process
Quantum properties of a superposition of squeezed displaced two-mode vacuum and single-photon states
International Nuclear Information System (INIS)
El-Orany, Faisal A A; Obada, A-S F; M Asker, Zafer; Perina, J
2009-01-01
In this paper, we study some quantum properties of a superposition of displaced squeezed two-mode vacuum and single-photon states, such as the second-order correlation function, the Cauchy-Schwarz inequality, quadrature squeezing, quasiprobability distribution functions and purity. These type of states include two mechanisms, namely interference in phase space and entanglement. We show that these states can exhibit sub-Poissonian statistics, squeezing and deviate from the classical Cauchy-Schwarz inequality. Moreover, the amount of entanglement in the system can be increased by increasing the squeezing mechanism. In the framework of the quasiprobability distribution functions, we show that the single-mode state can tend to the thermal state based on the correlation mechanism. A generation scheme for such states is given.
International Nuclear Information System (INIS)
Anton, M.A.; Calderon, Oscar G.; Carreno, F.
2004-01-01
In this paper we analyze the steady-state populations and gain lineshape of a V-type three-level atom with a closely spaced excited doublet. The atom is driven by a strong coherent field, a weak probe, and a single broadband squeezed vacuum. We focus our attention in the interplay between the quantum interference and the squeezed field on the probe gain. It is shown that the relative phases between the two coherent fields and the squeezed field play an important role in the optical properties of the atom. Specifically, we find that the probe can experience gain without population inversion for proper values of the parameters characterizing the squeezed field and in the absence of incoherent pumping. The system can be tailored to exhibit multiple dispersion regimes accompanied by negligible gain or absorption over a large bandwidth, a desirable feature for obtaining propagation of pulses with negligible distortion
International Nuclear Information System (INIS)
Ge, Wenchao; Bhattacharya, M
2016-01-01
Nonclassical states of macroscopic objects are promising for ultrasensitive metrology as well as testing quantum mechanics. In this work, we investigate dissipative mechanical quantum state engineering in an optically levitated nanodiamond. First, we study single-mode mechanical squeezed states by magnetically coupling the mechanical motion to a dressed three-level system provided by a nitrogen-vacancy center in the nanoparticle. Quantum coherence between the dressed levels is created via microwave fields to induce a two-phonon transition, which results in mechanical squeezing. Remarkably, we find that in ultrahigh vacuum quantum squeezing is achievable at room temperature with feedback cooling. For moderate vacuum, quantum squeezing is possible with cryogenic temperature. Second, we present a setup for two mechanical modes coupled to the dressed three levels, which results in two-mode squeezing analogous to the mechanism of the single-mode case. In contrast to previous works, our study provides a deterministic method for engineering macroscopic squeezed states without the requirement for a cavity. (paper)
Ge, Wenchao; Bhattacharya, M.
2016-10-01
Nonclassical states of macroscopic objects are promising for ultrasensitive metrology as well as testing quantum mechanics. In this work, we investigate dissipative mechanical quantum state engineering in an optically levitated nanodiamond. First, we study single-mode mechanical squeezed states by magnetically coupling the mechanical motion to a dressed three-level system provided by a nitrogen-vacancy center in the nanoparticle. Quantum coherence between the dressed levels is created via microwave fields to induce a two-phonon transition, which results in mechanical squeezing. Remarkably, we find that in ultrahigh vacuum quantum squeezing is achievable at room temperature with feedback cooling. For moderate vacuum, quantum squeezing is possible with cryogenic temperature. Second, we present a setup for two mechanical modes coupled to the dressed three levels, which results in two-mode squeezing analogous to the mechanism of the single-mode case. In contrast to previous works, our study provides a deterministic method for engineering macroscopic squeezed states without the requirement for a cavity.
Fractals as macroscopic manifestation of squeezed coherent states and brain dynamics
International Nuclear Information System (INIS)
Vitiello, Giuseppe
2012-01-01
Recent results on the relation between self-similarity and squeezed coherent states are presented. I consider fractals which are generated iteratively according to a prescribed recipe, the so-called deterministic fractals. Fractal properties are incorporated in the framework of the theory of the entire analytical functions and deformed coherent states. Conversely, fractal properties of squeezed coherent states are recognized. This sheds some light on the understanding of the dynamical origin of fractals and their global nature emerging from local deformation processes. The self-similarity in brain background activity suggested by laboratory observations of power-law distributions of power spectral densities of electrocorticograms is also discussed and accounted in the frame of the dissipative many-body model of brain.
O(N) symmetries, sum rules for generalized Hermite polynomials and squeezed states
International Nuclear Information System (INIS)
Daboul, Jamil; Mizrahi, Salomon S
2005-01-01
Quantum optics has been dealing with coherent states, squeezed states and many other non-classical states. The associated mathematical framework makes use of special functions as Hermite polynomials, Laguerre polynomials and others. In this connection we here present some formal results that follow directly from the group O(N) of complex transformations. Motivated by the squeezed states structure, we introduce the generalized Hermite polynomials (GHP), which include as particular cases, the Hermite polynomials as well as the heat polynomials. Using generalized raising operators, we derive new sum rules for the GHP, which are covariant under O(N) transformations. The GHP and the associated sum rules become useful for evaluating Wigner functions in a straightforward manner. As a byproduct, we use one of these sum rules, on the operator level, to obtain raising and lowering operators for the Laguerre polynomials and show that they generate an sl(2, R) ≅ su(1, 1) algebra
Decoherence and Fidelity in Teleportation of Coherent Photon-Added Two-Mode Squeezed Thermal States
Li, Heng-Mei; Yuan, Hong-Chun; Wan, Zhi-Long; Wang, Zhen
2018-04-01
We theoretically introduce a kind of non-Gaussian entangled resources, i.e., coherent photon-added two-mode squeezed thermal states (CPA-TMSTS), by successively performing coherent photon addition operation to the two-mode squeezed thermal states. The normalization factor related to bivariate Hermite polynomials is obtained. Based upon it, the nonclassicality and decoherence process are analyzed by virtue of the Wigner function. It is shown that the coherent photon addition operation is an effective way in generating partial negative values of Wigner function, which clearly manifests the nonclassicality and non-Gaussianity of the target states. Additionally, the fidelity in teleporting coherent states using CPA-TMSTS as entangled resource is quantified both analytically and numerically. It is found that the CPA-TMSTS is an entangled resource of high-efficiency and high-fidelity in quantum teleportation.
Back-action evasion and squeezing of a mechanical resonator using a cavity detector
Energy Technology Data Exchange (ETDEWEB)
Clerk, A A [Department of Physics, McGill University, Montreal, Quebec, H3A 2T8 (Canada); Marquardt, F [Department of Physics, Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, 80333 Munich (Germany); Jacobs, K [Department of Physics, University of Massachussets at Boston, Boston, MA 02125 (United States)], E-mail: aashish.clerk@mcgill.ca, E-mail: florian.marquardt@physik.uni-muenchen.de, E-mail: kjacobs@cs.umb.edu
2008-09-15
We study the quantum measurement of a cantilever using a parametrically coupled electromagnetic cavity which is driven at the two sidebands corresponding to the mechanical motion. This scheme, originally due to Braginsky et al (Braginsky V, Vorontsov Y I and Thorne K P 1980 Science 209 547), allows a back-action free measurement of one quadrature of the cantilever's motion, and hence the possibility of generating a squeezed state. We present a complete quantum theory of this system, and derive simple conditions on when the quantum limit on the added noise can be surpassed. We also study the conditional dynamics of the measurement, and discuss how such a scheme (when coupled with feedback) can be used to generate and detect squeezed states of the oscillator. Our results are relevant to experiments in optomechanics, and to experiments in quantum electromechanics employing stripline resonators coupled to mechanical resonators.
Plasmonic Moon: a Fano-like approach for squeezing the magnetic field in the infrared
Panaro, Simone
2015-08-11
Outstanding results have been achieved in the localization of optical electric fields via ultrasmall plasmonic cavities, paving the way to the subdiffractive confinement of local electromagnetic fields. However, due to the intrinsic constraints related to conventional architectures, no comparable squeezing factors have been managed yet for the magnetic counterpart of radiation, practically hindering the detection and manipulation of magneto-optical effects at the nanoscale. Here, we observe a strong magnetic field nanofocusing in the infrared, promoted by the induction of a coil-type Fano resonance. By triggering the coil current via a quadrupole-like plasmonic mode, we straightforwardly boost the enhancement of the infrared magnetic field and perform its efficient squeezing in localized nanovolumes.
Quantum key distribution with a single photon from a squeezed coherent state
International Nuclear Information System (INIS)
Matsuoka, Masahiro; Hirano, Takuya
2003-01-01
Squeezing of the coherent state by optical parametric amplifier is shown to efficiently produce single-photon states with reduced multiphoton probabilities compared with the weak coherent light. It can be a better source for a longer-distance quantum key distribution and also for other quantum optical experiments. The necessary condition for a secure quantum key distribution given by Brassard et al. is analyzed as functions of the coherent-state amplitude and squeeze parameter. Similarly, the rate of the gained secure bits G after error correction and privacy amplification given by Luetkenhaus is calculated. Compared with the weak coherent light, it is found that G is about ten times larger and its high level continues on about two times longer distance. By improvement of the detector efficiency it is shown that the distance extends further. Measurement of the intensity correlation function and the relation to photon antibunching are discussed for the experimental verification of the single-photon generation
Quantum cooling and squeezing of a levitating nanosphere via time-continuous measurements
Genoni, Marco G.; Zhang, Jinglei; Millen, James; Barker, Peter F.; Serafini, Alessio
2015-07-01
With the purpose of controlling the steady state of a dielectric nanosphere levitated within an optical cavity, we study its conditional dynamics under simultaneous sideband cooling and additional time-continuous measurement of either the output cavity mode or the nanosphere’s position. We find that the average phonon number, purity and quantum squeezing of the steady-states can all be made more non-classical through the addition of time-continuous measurement. We predict that the continuous monitoring of the system, together with Markovian feedback, allows one to stabilize the dynamics for any value of the laser frequency driving the cavity. By considering state of the art values of the experimental parameters, we prove that one can in principle obtain a non-classical (squeezed) steady-state with an average phonon number {n}{ph}≈ 0.5.
Entanglement concentration and purification of two-mode squeezed microwave photons in circuit QED
Zhang, Hao; Alsaedi, Ahmed; Hayat, Tasawar; Deng, Fu-Guo
2018-04-01
We present a theoretical proposal for a physical implementation of entanglement concentration and purification protocols for two-mode squeezed microwave photons in circuit quantum electrodynamics (QED). First, we give the description of the cross-Kerr effect induced between two resonators in circuit QED. Then we use the cross-Kerr media to design the effective quantum nondemolition (QND) measurement on microwave-photon number. By using the QND measurement, the parties in quantum communication can accomplish the entanglement concentration and purification of nonlocal two-mode squeezed microwave photons. We discuss the feasibility of our schemes by giving the detailed parameters which can be realized with current experimental technology. Our work can improve some practical applications in continuous-variable microwave-based quantum information processing.
Relieving the Time Squeeze? Effects of a White-Collar Workplace Change on Parents.
Hill, Rachelle; Tranby, Eric; Kelly, Erin; Moen, Phyllis
2013-08-01
Employed parents perceive a time squeeze even as trends from the 1960s show they are spending more time with their children. Work conditions (e.g., hours and schedule control) would seem to affect both parents' time with children and perceived time squeeze, but most studies rely on cross-sectional data that do not establish causality. The authors examined the effects of the introduction of a workplace flexibility initiative (Results Only Work Environment [ROWE]) on changes in mothers' and fathers' perceptions of the adequacy of their time with children and actual time spent with children ( N = 225). Baseline data show the importance of work conditions for parents' sense of perceived time adequacy. Panel data show that mothers (but not fathers) in ROWE report increased schedule control and improved time adequacy, but no change in actual time spent with children, except that ROWE increases evening meals with children for mothers sharing few meals at baseline.
Squeezed Dirac and Topological Magnons in a Bosonic Honeycomb Optical Lattice.
Owerre, Solomon; Nsofini, Joachim
2017-09-20
Quantum information storage using charge-neutral quasiparticles are expected to play a crucial role in the future of quantum computers. In this regard, magnons or collective spin-wave excitations in solid-state materials are promising candidates in the future of quantum computing. Here, we study the quantum squeezing of Dirac and topological magnons in a bosonic honeycomb optical lattice with spin-orbit interaction by utilizing the mapping to quantum spin-$1/2$ XYZ Heisenberg model on the honeycomb lattice with discrete Z$_2$ symmetry and a Dzyaloshinskii-Moriya interaction. We show that the squeezed magnons can be controlled by the Z$_2$ anisotropy and demonstrate how the noise in the system is periodically modified in the ferromagnetic and antiferromagnetic phases of the model. Our results also apply to solid-state honeycomb (anti)ferromagnetic insulators. . © 2017 IOP Publishing Ltd.
Cooling and squeezing the fluctuations of a nanomechanical beam by indirect quantum feedback control
International Nuclear Information System (INIS)
Zhang Jing; Liu Yuxi; Nori, Franco
2009-01-01
We study cooling and squeezing the fluctuations of a nanomechanical beam using quantum feedback control. In our model, the nanomechanical beam is coupled to a transmission line resonator via a superconducting quantum interference device. The leakage of the electromagnetic field from the transmission line resonator is measured using homodyne detection. This measured signal is then used to design a quantum feedback control signal to drive the electromagnetic field in the transmission line resonator. Although the control is imposed on the transmission line resonator, this quantum feedback control signal indirectly affects the thermal motion of the nanomechanical beam via the inductive beam-resonator coupling, making it possible to cool and squeeze the fluctuations of the beam, allowing it to approach the standard quantum limit.
Polarization Behavior of Squeeze Cast Al2O3 Fiber Reinforced Aluminum Matrix Composites
International Nuclear Information System (INIS)
Ham, S. H.; Kang, Y. C.; Cho, K. M.; Park, I. M.
1992-01-01
Electrochemical polarization behavior of squeeze cast Al 2 O 3 short fiber reinforced Al alloy matrix composites was investigated for the basic understanding of the corrosion properties of the composites. The composites were fabricated with variations of fiber volume fraction and matrix alloys. It was found that the reinforced composites are more susceptible to corrosion attack than the unreinforced matrix alloys in general. Corrosion resistance shows decreasing tendency with increasing Al 2 O 3 fiber volume fraction in AC8A matrix. Effect of the matrix alloys revealed that the AC8A Al matrix composite is less susceptible to corrosion attack than the 2024 and 7075 Al matrix composites. Effect of plastic deformation on electrochemical polarization behavior of the squeeze cast Al/Al 2 O 3 composites was examined after extrusion of AC8A-10v/o Al 2 O 3 . Result shows that corrosion resistance is deteriorated after plastic deformation
Mechanism and application of a newly developed pressure casting process: horizontal squeeze casting
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Li Peijie
2014-07-01
Full Text Available Compared to traditional high-pressure die casting (HPDC, horizontal squeeze casting (HSC is a more promising way to fabricate high-integrity castings, owing to a reduced number of gas and shrinkage porosities produced in the casting. In this paper, the differences between HSC and HPDC are assessed, through which it is shown that the cavity filling velocity and the size of the gating system to be the most notable differences. Equipment development and related applications are also reviewed. Furthermore, numerical simulation is used to analyze the three fundamental characteristics of HSC: slow cavity filling, squeeze feeding and slow sleeve filling. From this, a selection principle is given based on the three related critical casting parameters: cavity filling velocity, gate size and sleeve filling velocity. Finally, two specific applications of HSC are introduced, and the future direction of HSC development is discussed.
Squeezed Dirac and topological magnons in a bosonic honeycomb optical lattice
Owerre, S. A.; Nsofini, J.
2017-11-01
Quantum information storage using charge-neutral quasiparticles is expected to play a crucial role in the future of quantum computers. In this regard, magnons or collective spin-wave excitations in solid-state materials are promising candidates in the future of quantum computing. Here, we study the quantum squeezing of Dirac and topological magnons in a bosonic honeycomb optical lattice with spin-orbit interaction by utilizing the mapping to quantum spin-1/2 XYZ Heisenberg model on the honeycomb lattice with discrete Z2 symmetry and a Dzyaloshinskii-Moriya interaction. We show that the squeezed magnons can be controlled by the Z2 anisotropy and demonstrate how the noise in the system is periodically modified in the ferromagnetic and antiferromagnetic phases of the model. Our results also apply to solid-state honeycomb (anti)ferromagnetic insulators.
Quantum mechanical noise in coherent-state and squeezed-state Michelson interferometers
International Nuclear Information System (INIS)
Assaf, Ohad; Ben-Aryeh, Yacob
2002-01-01
In the present study we extend and generalize previous results for coherent-state and squeezed-state Michelson interferometer quantum mechanical uncertainties (or fluctuations), which are commonly referred to as 'quantum noise'. The calculation of photon counting (PC) fluctuations in the squeezed-state interferometer is extended to fourth-order correlation functions used as the measured signal. We also generalize a 'unified model' for treating both PC and radiation pressure fluctuations in the coherent-state interferometer, by using mathematical methods which apply to Kerr-type interactions. The results are more general than those reported previously in two ways. First, we obtain exact expressions, which lead to previous results under certain approximations. Second, we deal with cases in which the responses of the two mirrors to radiation pressure are not equal
Modeling of magnetorheological fluid in quasi-static squeeze flow mode
Horak, Wojciech
2018-06-01
This work presents a new nonlinear model to describe MR fluid behavior in the squeeze flow mode. The basis for deriving the model were the principles of continuum mechanics and the theory of tensor transformation. The analyzed case concerned quasi-static squeeze with a constant area, between two parallel plates with non-slip boundary conditions. The developed model takes into account the rheological properties or MR fluids as a viscoplastic material for which yield stress increases due to compression. The model also takes into account the formation of normal force in the MR fluid as a result of the magnetic field impact. Moreover, a new parameter has been introduced which characterizes the behavior of MR fluid subjected to compression. The proposed model has been experimentally validated and the obtained results suggest that the assumptions made in the model development are reasonable, as good model compatibility with the experiments was obtained.
Water-based squeezing flow in the presence of carbon nanotubes between two parallel disks
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Haq Rizwan Ul
2016-01-01
Full Text Available Present study is dedicated to investigate the water functionalized carbon nanotubes squeezing flow between two parallel discs. Moreover, we have considered magnetohydrodynamics effects normal to the disks. In addition we have considered two kind of carbon nanotubes named: single wall carbon nanotubes (SWCNT and multiple wall carbon nanotubes (MWCNT with in the base fluid. Under this squeezing flow mechanism model has been constructed in the form of partial differential equation. Transformed ordinary differential equations are solved numerically with the help of Runge-Kutta-Fehlberg method. Results for velocity and temperature are constructed against all the emerging parameters. Comparison among the SWCNT and MWCNT are drawn for skin friction coefficient and local Nusselt number. Conclusion remarks are drawn under the observation of whole analysis.
The solutions of Navier-Stokes equations in squeezing flow between parallel plates
Czech Academy of Sciences Publication Activity Database
Petrov, A. G.; Kharlamova, Irina
2014-01-01
Roč. 48, November–December (2014), s. 40-48 ISSN 0997-7546 Grant - others:Russian Foundation for Basic Research(RU) 14-01- 00818; Russian Foundation for Basic Research(RU) 14-01-00892 Institutional support: RVO:67985874 Keywords : closed form solution * Navier-Stokes equations * squeezing flow between plates * counterflow Subject RIV: BK - Fluid Dynamics Impact factor: 1.656, year: 2014
Squeezing flow viscometry for nonelastic semiliquid foods--theory and applications.
Campanella, Osvaldo H; Peleg, Micha
2002-01-01
In most conventional rheometers, notably the coaxial cylinders and capillary viscometers, the food specimen is pressed into a narrow gap and its structure is altered by uncontrolled shear. Also, most semiliquid foods exhibit slip, and consequently the measurements do not always reflect their true rheological properties. A feasible solution to these two problems is squeezing flow viscometry where the specimen, practically intact and with or without suspended particles, is squeezed between parallel plates. The outward flow pattern mainly depends on the friction between the fluid and plates or its absence ("lubricated squeezing flow"). Among the possible test geometries, the one of constant area and changing volume is the most practical for foods. The test can be performed at a constant displacement rate using common Universal Testing Machines or under constant loads (creep array). The tests output is in the form of a force-height, force-time, or height-time relationship, from which several rheological parameters can be derived. With the current state of the art, the method can only be applied at small displacement rates. Despite the method's crudeness, its results are remarkably reproducible and sensitive to textural differences among semiliquid food products. The flow patterns observed in foods do not always follow the predictions of rheological models originally developed for polymer melts because of the foods' unique microstructures. The implications of these discrepancies and the role that artifacts may play are evaluated in light of theoretical and practical considerations. The use of squeezing flow viscometry to quantify rheological changes that occur during a product's handling and to determine whether they are perceived sensorily is suggested.
International Nuclear Information System (INIS)
Fernandez, A. M.; Sanchez-Ledesma, D. M.; Tournassat, C.; Melon, A.; Gaucher, E.; Astudillo, E.; Vinsot, A.
2013-01-01
Knowledge of the pore water chemistry in clay rock formations plays an important role in determining radionuclide migration in the context of nuclear waste disposal. Among the different in situ and ex-situ techniques for pore water sampling in clay sediments and soils, squeezing technique dates back 115 years. Although different studies have been performed about the reliability and representativeness of squeezed pore waters, more of them were achieved on high porosity, high water content and unconsolidated clay sediments. A very few of them tackled the analysis of squeezed pore water from low-porosity, low water content and highly consolidated clay rocks. In this work, a specially designed and fabricated one-dimensional compression cell two directional fluid flow was used to extract and analyse the pore water composition of Opalinus Clay core samples from Mont Terri (Switzerland). The reproducibility of the technique is good and no ionic ultrafiltration, chemical fractionation or anion exclusion was found in the range of pressures analysed: 70-200 MPa. Pore waters extracted in this range of pressures do not decrease in concentration, which would indicate a dilution of water by mixing of the free pore water and the outer layers of double layer water (Donnan water). A threshold (safety) squeezing pressure of 175 MPa was established for avoiding membrane effects (ion filtering, anion exclusion, etc.) from clay particles induced by increasing pressures. Besides, the pore waters extracted at these pressures are representative of the Opalinus Clay formation from a direct comparison against in situ collected borehole waters. (Author)
Energy Technology Data Exchange (ETDEWEB)
Fernandez, A. M.; Sanchez-Ledesma, D. M.; Tournassat, C.; Melon, A.; Gaucher, E.; Astudillo, E.; Vinsot, A.
2013-07-01
Knowledge of the pore water chemistry in clay rock formations plays an important role in determining radionuclide migration in the context of nuclear waste disposal. Among the different in situ and ex-situ techniques for pore water sampling in clay sediments and soils, squeezing technique dates back 115 years. Although different studies have been performed about the reliability and representativeness of squeezed pore waters, more of them were achieved on high porosity, high water content and unconsolidated clay sediments. A very few of them tackled the analysis of squeezed pore water from low-porosity, low water content and highly consolidated clay rocks. In this work, a specially designed and fabricated one-dimensional compression cell two directional fluid flow was used to extract and analyse the pore water composition of Opalinus Clay core samples from Mont Terri (Switzerland). The reproducibility of the technique is good and no ionic ultrafiltration, chemical fractionation or anion exclusion was found in the range of pressures analysed: 70-200 MPa. Pore waters extracted in this range of pressures do not decrease in concentration, which would indicate a dilution of water by mixing of the free pore water and the outer layers of double layer water (Donnan water). A threshold (safety) squeezing pressure of 175 MPa was established for avoiding membrane effects (ion filtering, anion exclusion, etc.) from clay particles induced by increasing pressures. Besides, the pore waters extracted at these pressures are representative of the Opalinus Clay formation from a direct comparison against in situ collected borehole waters. (Author)
Reduction of quantum noise in the Michelson interferometer by use of squeezed vacuum states
International Nuclear Information System (INIS)
Assaf, Ohad; Ben-Aryeh, Yacob
2002-01-01
We develop further the unified model for treating photon-counting and radiation-pressure fluctuations in the Michelson interferometer with input of squeezed vacuum state. The dependence of the quantum fluctuations on the phase of the input light is calculated. The analysis is restricted to a single-mode interferometer, but generalized in a way that includes both harmonic-oscillator and floating mirrors. We compare our results with those of other authors
Viscosity of particle laden films
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Timounay Yousra
2017-01-01
Full Text Available We perform retraction experiments on soap films where large particles bridge the two interfaces. Local velocities are measured by PIV during the unstationnary regime. The velocity variation in time and space can be described by a continuous fluid model from which effective viscosity (shear and dilatational of particulate films is measured. The 2D effective viscosity of particulate films η2D increases with particle surface fraction ϕ: at low ϕ, it tends to the interfacial dilatational viscosity of the liquid/air interfaces and it diverges at the critical particle surface fraction ϕc ≃ 0.84. Experimental data agree with classical viscosity laws of hard spheres suspensions adapted to the 2D geometry, assuming viscous dissipation resulting from the squeeze of the liquid/air interfaces between the particles. Finally, we show that the observed viscous dissipation in particulate films has to be considered to describe the edge velocity during a retraction experiment at large particle coverage.
NATO Advanced Research Workshop on Squeezed and Non-classical Light
Pike, E; Squeezed and Non-classical Light
1988-01-01
The recent generation in the laboratory of phase squeezed and intensity squeezed light beams has brought to fruition the theoretical predictions of such non-classical phenomena which have been made and developed in recent years by a number of workers in the field of quantum optics. A vigorous development is now underway of both theory and experiment and the first measurements have been coi:Jfirmed and extended already in some half dozen laboratories. Although the fields of application of these novellight sources are as yet somewhat hazy in our minds and some inspired thinking is required along these lines, the pace and excitement of the research is very clear. It is to he hoped that the new possibilities of: making measurements below the quantum shot noise lirnit which is made possible by these squeezed states of light willlead to further fundamental advances in the near future. In this NATO ARW a number of the leaders in the field met in the extremely pleasant surroundings of Cortina d'Ampezzo and th...
Structure of multiphoton quantum optics. I. Canonical formalism and homodyne squeezed states
dell'Anno, Fabio; de Siena, Silvio; Illuminati, Fabrizio
2004-03-01
We introduce a formalism of nonlinear canonical transformations for general systems of multiphoton quantum optics. For single-mode systems the transformations depend on a tunable free parameter, the homodyne local-oscillator angle; for n -mode systems they depend on n heterodyne mixing angles. The canonical formalism realizes nontrivial mixing of pairs of conjugate quadratures of the electromagnetic field in terms of homodyne variables for single-mode systems, and in terms of heterodyne variables for multimode systems. In the first instance the transformations yield nonquadratic model Hamiltonians of degenerate multiphoton processes and define a class of non-Gaussian, nonclassical multiphoton states that exhibit properties of coherence and squeezing. We show that such homodyne multiphoton squeezed states are generated by unitary operators with a nonlinear time evolution that realizes the homodyne mixing of a pair of conjugate quadratures. Tuning of the local-oscillator angle allows us to vary at will the statistical properties of such states. We discuss the relevance of the formalism for the study of degenerate (up-)down-conversion processes. In a companion paper [ F. Dell’Anno, S. De Siena, and F. Illuminati, 69, 033813 (2004) ], we provide the extension of the nonlinear canonical formalism to multimode systems, we introduce the associated heterodyne multiphoton squeezed states, and we discuss their possible experimental realization.
Comment on ''Teleportation of two-mode squeezed states''
Energy Technology Data Exchange (ETDEWEB)
He Guangqiang; Zhang Jingtao [State Key Lab of Advanced Optical Communication Systems and Networks Department of Electronic Engineering, Shanghai Jiaotong University, Shanghai 200030 (China)
2011-10-15
We investigate the teleportation scheme of two-mode squeezed states proposed by Adhikari et al.[S. Adhikari et al., Phys. Rev. A 77, 012337 (2008)]. It uses four-mode entangled states to teleport two-mode squeezed states. The fidelity between the original two-mode squeezed states and teleported ones is calculated. The maximal fidelity value of Adhikari's protocol is 0.38, which is incompatible with the fidelity definition with the maximal value 1. In our opinion, one reason is that they calculate the fidelity for multimodes Gaussian states using the fidelity formula for single-mode ones. Another reason is that the covariance matrix of output states should be what is obtained after applying the linear unitary Bogoliubov operations (two cascaded Fourier transformations) on the covariance matrix given in Eq. (12) in their paper. These two reasons result in the incomparable results. In addition, Adhikari's protocol can be simplified to be easily implemented.
Directory of Open Access Journals (Sweden)
Vanessa S. Pereira
2014-10-01
Full Text Available Background: The proper evaluation of the pelvic floor muscles (PFM is essential for choosing the correct treatment. Currently, there is no gold standard for the assessment of female PFM function. Objective: To determine the correlation between vaginal palpation, vaginal squeeze pressure, and electromyographic and ultrasonographic variables of the female PFM. Method: This cross-sectional study evaluated 80 women between 18 and 35 years of age who were nulliparous and had no pelvic floor dysfunction. PFM function was assessed based on digital palpation, vaginal squeeze pressure, electromyographic activity, bilateral diameter of the bulbocavernosus muscles and the amount of bladder neck movement during voluntary PFM contraction using transperineal bi-dimensional ultrasound. The Pearson correlation was used for statistical analysis (p<0.05. Results: There was a strong positive correlation between PFM function and PFM contraction pressure (0.90. In addition, there was a moderate positive correlation between these two variables and PFM electromyographic activity (0.59 and 0.63, respectively and movement of the bladder neck in relation to the pubic symphysis (0.51 and 0.60, respectively. Conclusions: This study showed that there was a correlation between vaginal palpation, vaginal squeeze pressure, and electromyographic and ultrasonographic variables of the PFM in nulliparous women. The strong correlation between digital palpation and PFM contraction pressure indicated that perineometry could easily be replaced by PFM digital palpation in the absence of equipment.
China’s marriage squeeze: A decomposition into age and sex structure
LI, Xiaomin; LI, Shuzhuo; FELDMAN, Marcus W.
2016-01-01
Most recent studies of marriage patterns in China have emphasized the male-biased sex ratio but have largely neglected age structure as a factor in China’s male marriage squeeze. In this paper we develop an index we call “spousal sex ratio” (SSR) to measure the marriage squeeze, and a method of decomposing the proportion of male surplus into age and sex structure effects within a small spousal age difference interval. We project that China’s marriage market will be confronted with a relatively severe male squeeze. For the decomposition of the cohort aged 30, from 2010 to 2020 age structure will be dominant, while from 2020 through 2034 the contribution of age structure will gradually decrease and that of sex structure will increase. From then on, sex structure will be dominant. The index and decomposition, concentrated on a specific female birth cohort, can distinguish spousal competition for single cohorts which may be covered by a summary index for the whole marriage market; these can also be used for consecutive cohorts to reflect the situation of the whole marriage market. PMID:27242390
Structure of multiphoton quantum optics. I. Canonical formalism and homodyne squeezed states
International Nuclear Information System (INIS)
Dell'Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio
2004-01-01
We introduce a formalism of nonlinear canonical transformations for general systems of multiphoton quantum optics. For single-mode systems the transformations depend on a tunable free parameter, the homodyne local-oscillator angle; for n-mode systems they depend on n heterodyne mixing angles. The canonical formalism realizes nontrivial mixing of pairs of conjugate quadratures of the electromagnetic field in terms of homodyne variables for single-mode systems, and in terms of heterodyne variables for multimode systems. In the first instance the transformations yield nonquadratic model Hamiltonians of degenerate multiphoton processes and define a class of non-Gaussian, nonclassical multiphoton states that exhibit properties of coherence and squeezing. We show that such homodyne multiphoton squeezed states are generated by unitary operators with a nonlinear time evolution that realizes the homodyne mixing of a pair of conjugate quadratures. Tuning of the local-oscillator angle allows us to vary at will the statistical properties of such states. We discuss the relevance of the formalism for the study of degenerate (up-)down-conversion processes. In a companion paper [F. Dell'Anno, S. De Siena, and F. Illuminati, 69, 033813 (2004)], we provide the extension of the nonlinear canonical formalism to multimode systems, we introduce the associated heterodyne multiphoton squeezed states, and we discuss their possible experimental realization
Directory of Open Access Journals (Sweden)
Manjunath Patel Gowdru Chandrashekarappa
2014-01-01
Full Text Available The present research work is focussed to develop an intelligent system to establish the input-output relationship utilizing forward and reverse mappings of artificial neural networks. Forward mapping aims at predicting the density and secondary dendrite arm spacing (SDAS from the known set of squeeze cast process parameters such as time delay, pressure duration, squeezes pressure, pouring temperature, and die temperature. An attempt is also made to meet the industrial requirements of developing the reverse model to predict the recommended squeeze cast parameters for the desired density and SDAS. Two different neural network based approaches have been proposed to carry out the said task, namely, back propagation neural network (BPNN and genetic algorithm neural network (GA-NN. The batch mode of training is employed for both supervised learning networks and requires huge training data. The requirement of huge training data is generated artificially at random using regression equation derived through real experiments carried out earlier by the same authors. The performances of BPNN and GA-NN models are compared among themselves with those of regression for ten test cases. The results show that both models are capable of making better predictions and the models can be effectively used in shop floor in selection of most influential parameters for the desired outputs.
Update on the status of hadronic squeezed correlations at RHIC energies
International Nuclear Information System (INIS)
Padula, S.S.; Dudek, D.M.; Socolowski, O. Jr.
2011-01-01
In high-energy heavy-ion collisions, a hot and dense medium is formed, where the hadronic masses may be shifted from their asymptotic values. If this mass modification occurs, squeezed back-to-back correlations (BBC) of particle-antiparticle pairs are predicted to appear, both in the fermionic (fBBC) and in the bosonic (bBBC) sectors. Although they have unlimited intensity even for finite-size expanding systems, these hadronic squeezed correlations are very sensitive to their time emission distribution. Here we discuss results in case this time emission is parameterized by a Levy-type distribution, showing that it reduces the signal even more dramatically than a Lorentzian distribution, which already reduces the intensity of the effect by orders of magnitude, as compared to the sudden emission. However, we show that the signal could still survive if the duration of the process is short, and if the effect is searched for lighter mesons, such as kaons. We compare some of our results to recent PHENIX preliminary data on squeezed correlations of K + K - pairs
Exploring imperfect squeezing flow measurements in a Teflon geometry for semisolid foods.
Terpstra, M E J; Janssen, A M; Linden, E van der
2007-11-01
The method of imperfect lubricated squeezing flow in a Teflontrade mark geometry has been explored for the characterization of elongational behavior of custard and mayonnaise. Two Newtonian products, one of low (0.07 Pas) and one of high (18 Pas) shear viscosity, were used as references. Measurements of custards and mayonnaises did not behave according to either the theory of lubricated or nonlubricated squeezing flow, as there were effects of the initial sample height and compression speed. Also, calculated values for the flow index were not as we had expected. The same was true for the Newtonian samples. An important factor explaining the effect of compression speed was the presence of a certain amount of friction, rendering both lubricated theory and nonlubricated theory nonapplicable. Correcting for (pseudo-) thixotropic behavior of custard and mayonnaise appears to be an effective way of obtaining realistic values for the flow index. The presence of buoyancy also affected the results, especially in the case of low viscous products and the effect of initial sample height. Other factors that played a role in the results were yield stress for custard and mayonnaise and instrumental artifacts associated with the imperfect setup of the measurement, especially for the highly viscous products. Quantitatively correcting the results for all of these factors is not possible at this point. Although the imperfect squeezing flow technique in a Teflon geometry is a very practical way to measure semisolids such as custard and mayonnaise under (partly) elongational deformation, the results should be regarded as more qualitative than quantitative.
3D modeling of squeeze flow of unidirectionally thermoplastic composite inserts
Ghnatios, Chady; Abisset-Chavanne, Emmanuelle; Binetruy, Christophe; Chinesta, Francisco; Advani, Suresh
2016-10-01
Thermoplastic composites are attractive because they can be recycled and exhibit superior mechanical properties. The ability of thermoplastic resin to melt and solidify allows for fast and cost-effective manufacturing processes, which is a crucial property for high volume production. Thermoplastic composite parts are usually obtained by stacking several prepreg plies to create a laminate with a particular orientation sequence to meet design requirements. During the consolidation and forming process, the thermoplastic laminate is subjected to complex deformation which can include intraply and/or interply shear, ply reorientation and squeeze flow. In the case of unidirectional prepregs, the ply constitutive equation, when elastic effects are neglected, can be modeled as a transversally isotropic fluid, that must satisfy the fiber inextensibility as well as the fluid incompressibility. The high-fidelity solution of the squeeze flow in laminates composed of unidirectional prepregs was addressed in our former works by making use of an in-plane-out-of-plane separated representation allowing a very detailed resolution of the involved fields throughout the laminate thickness. In the present work prepregs plies are supposed of limited dimensions compared to the in-plane dimension of the part and will be named inserts. Again within the Proper Generalized Decomposition framework high-resolution simulation of the squeeze flow occurring during consolidation is addressed within a fully 3D in-plane-out-of-plane separated representation.
Application of lift and squeeze technique in phacoemulsification of hypermature cataract
Directory of Open Access Journals (Sweden)
Geng-Ying Li
2014-07-01
Full Text Available AIM: To evaluate the effectiveness and security of lift and squeeze technique in phacoemulsification of hypermature cataract.METHODS: From June 2010 to June 2013, totally 156 eyes with hypermature cataract, which received phacoemulsification in our hospital, were enrolled. Lift and squeeze technique was used to chop the nucleus, and 1g/L Trypan blue was used for capsulorhexis. Average time of phaco complication, corneal edema and visual outcome were recorded.RESULTS: The best-corrected visual acuity(BCVA was 0.1-0.4 in 15 eyes(9.6%, 0.5-0.7 in 82(52.6%eyes, and 0.8-1.0 in 59(37.8%eyes at 3mo after surgery. The phaco time was 25-56s(average 42±10s, the maximum phaco power was 30%. Posterior capsular rupture and vitreous loss happened in 2 eyes(1.3%, and the IOLs were implanted in the sulcus. Corneal edema classified at grade Ⅰ were seen in 12 eyes(7.7%, and 5 eyes(3.2%at gradeⅡ, no eye at grade Ⅲ and grade Ⅳ. The mean endothelial cell loss was 8.7% at 3mo.CONCLUSION: Crystalline lens capsule staining with Trypan blue increase the success rate of intact continuous curvilinear capsulorhexis(CCC. The lift and squeeze technique reduces the stress on the zonules and capsule, and decreases the phaco time and phaco power.
Squeeze-SegNet: a new fast deep convolutional neural network for semantic segmentation
Nanfack, Geraldin; Elhassouny, Azeddine; Oulad Haj Thami, Rachid
2018-04-01
The recent researches in Deep Convolutional Neural Network have focused their attention on improving accuracy that provide significant advances. However, if they were limited to classification tasks, nowadays with contributions from Scientific Communities who are embarking in this field, they have become very useful in higher level tasks such as object detection and pixel-wise semantic segmentation. Thus, brilliant ideas in the field of semantic segmentation with deep learning have completed the state of the art of accuracy, however this architectures become very difficult to apply in embedded systems as is the case for autonomous driving. We present a new Deep fully Convolutional Neural Network for pixel-wise semantic segmentation which we call Squeeze-SegNet. The architecture is based on Encoder-Decoder style. We use a SqueezeNet-like encoder and a decoder formed by our proposed squeeze-decoder module and upsample layer using downsample indices like in SegNet and we add a deconvolution layer to provide final multi-channel feature map. On datasets like Camvid or City-states, our net gets SegNet-level accuracy with less than 10 times fewer parameters than SegNet.
Lance, Larry M.; Atwater, Lynn
1987-01-01
Reviews four Human Sexuality films and videos. These are: "Personal Decisions" (Planned Parenthood Federation of America, 1985); "The Touch Film" (Sterling Production, 1986); "Rethinking Rape" (Film Distribution Center, 1985); "Not A Love Story" (National Film Board of Canada, 1981). (AEM)
Directory of Open Access Journals (Sweden)
A. O. Shvets
2015-06-01
Full Text Available Purpose. Despite of the implementation various programs to improve the safety of train traffic problem of reducing gatherings rolling stock off the rails is still relevant. The study aims to clarify the existing method of determining the factor of stability from the tire longitudinal forces to ensure the sustainability of cars with increasing speeds of the rolling stock. Methodology. Research was conducted by the method of mathematical modeling of loading freight car when driving at different speeds on straight and curved track sections. Findings. Analysis of the results shows that, for all selected freight cars for the calculation, the value of the safety factor by squeezing is smaller than the formulas of Standards. Corrections made to the formula for determining the safety factor by squeezing longitudinal forces, would achieve: 1 a higher safety factor of lightweight cars, excluding them squeezing longitudinal forces in the entire range of speeds of freight trains; 2 to develop and implement measures to prevent squeezing of cars in the entire range of motion; 3 to determine the degree of stability of the empty car in the head, middle and tail laden trains; 4 to offer optimal scheme of mixed trains formation. Originality. The analysis of existing methods for determining stability coefficient cars in freight trains from squeezing their longitudinal forces is presented in studies. Proposals are developed for the refinement of the design phase, construction and operation. Practical value. This study clarifies the existing method of determining the safety factor of stability from the squeezing longitudinal forces, as well as the influence on the magnitude of the coefficient of speed of movement of the rolling stock. Developed proposals for the refinement of existing methods for determining stability coefficient of longitudinal forces squeezing cars in a train, can reduce the number of retirements cars derailed by taking into account in the
Social Support Networks and Quality of Life of Rural Men in a Context of Marriage Squeeze in China.
Wang, Sasa; Yang, Xueyan; Attané, Isabelle
2018-07-01
A significant number of rural Chinese men are facing difficulties in finding a spouse and may fail to ever marry due to a relative scarcity of women in the adult population. Research has indicated that marriage squeeze is a stressful event which is harmful to men's quality of life, and also weakens their social support networks. Using data collected in rural Chaohu city, Anhui, China, this study explores the effects of social support networks on quality of life of rural men who experience a marriage squeeze. The results indicate that the size of social contact networks is directly and positively associated with the quality of life of marriage-squeezed men, and moderate the negative effect of age on quality of life. Having no or limited instrumental support network and social contact network are double-edged swords, which have direct negative associations with the quality of life of marriage-squeezed men, and have moderate effects on the relationship between marriage squeeze and quality of life.
Noncritical quadrature squeezing in two-transverse-mode optical parametric oscillators
International Nuclear Information System (INIS)
Navarrete-Benlloch, Carlos; Roldan, Eugenio; Valcarcel, German J. de; Romanelli, Alejandro
2010-01-01
In this article we explore the quantum properties of a degenerate optical parametric oscillator when it is tuned to the first family of transverse modes at the down-converted frequency. Recently we found [C. Navarrete-Benlloch et al., Phys. Rev. Lett. 100, 203601 (2008)] that above threshold a TEM 10 mode following a random rotation in the transverse plane emerges in this system (we denote it as the bright mode), breaking thus its rotational invariance. Then, owing to the mode orientation being undetermined, we showed that the phase quadrature of the transverse mode orthogonal to this one (denoted as the dark mode) is perfectly squeezed at any pump level and without an increase in the fluctuations on its amplitude quadrature (which seems to contradict the uncertainty principle). In this article we go further in the study of this system and analyze some important features not considered previously. First we show that the apparent violation of the uncertainty principle is just that -'apparent' - as the conjugate pair of the squeezed quadrature is not another quadrature but the orientation of the bright mode (which is completely undetermined in the long term). We also study a homodyne scheme in which the local oscillator is not perfectly matched to the dark mode, as this could be impossible in real experiments due to the random rotation of the mode, showing that even in this case large levels of noise reduction can be obtained (also including the experimentally unavoidable phase fluctuations). Finally, we show that neither the adiabatic elimination of the pump variables nor the linearization of the quantum equations are responsible for the remarkable properties of the dark mode (which we prove analytically and through numerical simulations, respectively), which were simplifying assumptions used in Navarrete-Benlloch et al. [Phys. Rev. Lett. 100, 203601 (2008)]. These studies show that the production of noncritically squeezed light through spontaneous rotational
Squeezed states of the generalized minimum uncertainty state for the Caldirola-Kanai Hamiltonian
International Nuclear Information System (INIS)
Kim, Sang Pyo
2003-01-01
We show that the ground state of the well-known pseudo-stationary states for the Caldirola-Kanai Hamiltonian is a generalized minimum uncertainty state, which has the minimum allowed uncertainty ΔqΔp = ℎσ 0 /2, where σ 0 (≥1) is a constant depending on the damping factor and natural frequency. The most general symmetric Gaussian states are obtained as the one-parameter squeezed states of the pseudo-stationary ground state. It is further shown that the coherent states of the pseudo-stationary ground state constitute another class of the generalized minimum uncertainty states
Displacement-enhanced entanglement distillation of single-mode-squeezed entangled states
DEFF Research Database (Denmark)
Tipsmark, Anders; Neergaard-Nielsen, Jonas Schou; Andersen, Ulrik Lund
2013-01-01
It has been shown that entanglement distillation of Gaussian entangled states by means of local photon subtraction can be improved by local Gaussian transformations. Here we show that a similar effect can be expected for the distillation of an asymmetric Gaussian entangled state that is produced...... by a single squeezed beam. We show that for low initial entanglement, our largely simplified protocol generates more entanglement than previous proposed protocols. Furthermore, we show that the distillation scheme also works efficiently on decohered entangled states as well as with a practical photon...
International Nuclear Information System (INIS)
Zhang Sheng; Wang Jian; Tang Chaojing; Zhang Quan
2011-01-01
It is established that a single quantum cryptography protocol usually cooperates with other cryptographic systems, such as an authentication system, in the real world. However, few protocols have been proposed on how to combine two or more quantum protocols. To fill this gap, we propose a composed quantum protocol, containing both quantum identity authentication and quantum key distribution, using squeezed states. Hence, not only the identity can be verified, but also a new private key can be generated by our new protocol. We also analyze the security under an optimal attack, and the efficiency, which is defined by the threshold of the tolerant error rate, using Gaussian error function. (general)
Rubidium resonant squeezed light from a diode-pumped optical-parametric oscillator
Predojevic, Ana
2009-01-01
La luz comprimida (squeezed light) es uno de los componentes importantes de los experimentos de memorias cuánticas. Un almacenamiento eficientede la luz comprimida en una colectividad de átomos exige que la luz (comprimida) sea resonante a la línea espectral de absorción. El láser de diodopuede acceder a una amplia clase de líneas espectrales dado al amplio rango de longitudes de onda accesibles. Por lo tanto, el uso de fuentes de luz comprimida basadas en láseres de diodo ampliaría el número...
Quantum entropy and uncertainty for two-mode squeezed, coherent and intelligent spin states
Aragone, C.; Mundarain, D.
1993-01-01
We compute the quantum entropy for monomode and two-mode systems set in squeezed states. Thereafter, the quantum entropy is also calculated for angular momentum algebra when the system is either in a coherent or in an intelligent spin state. These values are compared with the corresponding values of the respective uncertainties. In general, quantum entropies and uncertainties have the same minimum and maximum points. However, for coherent and intelligent spin states, it is found that some minima for the quantum entropy turn out to be uncertainty maxima. We feel that the quantum entropy we use provides the right answer, since it is given in an essentially unique way.
Entangling different degrees of freedom by quadrature squeezing cylindrically polarized modes
DEFF Research Database (Denmark)
Gabriel, C.; Aiello, A.; Zhong, W.
2011-01-01
Quantum systems such as, for example, photons, atoms, or Bose-Einstein condensates, prepared in complex states where entanglement between distinct degrees of freedom is present, may display several intriguing features. In this Letter we introduce the concept of such complex quantum states...... generates entanglement between these two different degrees of freedom. Experimentally we demonstrate amplitude squeezing of an azimuthally polarized mode by exploiting the nonlinear Kerr effect in a specially tailored photonic crystal fiber. These results display that such novel continuous......-variable entangled systems can, in principle, be realized.© 2011 American Physical Society....
A continuous variable quantum deterministic key distribution based on two-mode squeezed states
International Nuclear Information System (INIS)
Gong, Li-Hua; Song, Han-Chong; Liu, Ye; Zhou, Nan-Run; He, Chao-Sheng
2014-01-01
The distribution of deterministic keys is of significance in personal communications, but the existing continuous variable quantum key distribution protocols can only generate random keys. By exploiting the entanglement properties of two-mode squeezed states, a continuous variable quantum deterministic key distribution (CVQDKD) scheme is presented for handing over the pre-determined key to the intended receiver. The security of the CVQDKD scheme is analyzed in detail from the perspective of information theory. It shows that the scheme can securely and effectively transfer pre-determined keys under ideal conditions. The proposed scheme can resist both the entanglement and beam splitter attacks under a relatively high channel transmission efficiency. (paper)
International Nuclear Information System (INIS)
Dalton, B J; Goold, J; Garraway, B M; Reid, M D
2017-01-01
These two accompanying papers are concerned with entanglement for systems of identical massive bosons and the relationship to spin squeezing and other quantum correlation effects. The main focus is on two mode entanglement, but multi-mode entanglement is also considered. The bosons may be atoms or molecules as in cold quantum gases. The previous paper I dealt with the general features of quantum entanglement and its specific definition in the case of systems of identical bosons. Entanglement is a property shared between two (or more) quantum sub-systems. In defining entanglement for systems of identical massive particles, it was concluded that the single particle states or modes are the most appropriate choice for sub-systems that are distinguishable, that the general quantum states must comply both with the symmetrization principle and the super-selection rules (SSR) that forbid quantum superpositions of states with differing total particle number (global SSR compliance). Further, it was concluded that (in the separable states) quantum superpositions of sub-system states with differing sub-system particle number (local SSR compliance) also do not occur. The present paper II determines possible tests for entanglement based on the treatment of entanglement set out in paper I. Several inequalities involving variances and mean values of operators have been previously proposed as tests for entanglement between two sub-systems. These inequalities generally involve mode annihilation and creation operators and include the inequalities that define spin squeezing. In this paper, spin squeezing criteria for two mode systems are examined, and spin squeezing is also considered for principle spin operator components where the covariance matrix is diagonal. The proof, which is based on our SSR compliant approach shows that the presence of spin squeezing in any one of the spin components requires entanglement of the relevant pair of modes. A simple Bloch vector test for
Squeezing of open boundaries by Maxwell-consistent real coordinate transformation
DEFF Research Database (Denmark)
Shyroki, Dzmitry
2006-01-01
To emulate open boundaries within a finite computational domain, real-function coordinate transformation consistent with generally covariant Maxwell equations is proposed. The mapping-realized with arctangent function here-has a transparent geometric meaning of pure squeezing of coordinates, does...... not introduce artificially lossy layers (or "lossy coordinates") to absorb outgoing radiation, nor lead to spurious non-Maxwellian fields. In finite-difference frequency-domain calculations on staggered grid, clear superiority over perfectly matched layers is demonstrated by the proposed technique, at a lower...
Mechanical design and analysis of a low beta squeezed half-wave resonator
He, Shou-Bo; Zhang, Cong; Yue, Wei-Ming; Wang, Ruo-Xu; Xu, Meng-Xin; Wang, Zhi-Jun; Huang, Shi-Chun; Huang, Yu-Lu; Jiang, Tian-Cai; Wang, Feng-Feng; Zhang, Sheng-Xue; He, Yuan; Zhang, Sheng-Hu; Zhao, Hong-Wei
2014-08-01
A superconducting squeezed type half-wave resonator (HWR) of β=0.09 has been developed at the Institute of Modern Physics, Lanzhou. In this paper, a basic design is presented for the stiffening structure for the detuning effect caused by helium pressure and Lorentz force. The mechanical modal analysis has been investigated the with finite element method (FEM). Based on these considerations, a new stiffening structure is proposed for the HWR cavity. The computation results concerning the frequency shift show that the low beta HWR cavity with new stiffening structure has low frequency sensitivity coefficient df/dp and Lorentz force detuning coefficient KL, and stable mechanical properties.
Squeezing based on nondegenerate frequency doubling internal to a realistic laser
DEFF Research Database (Denmark)
Andersen, Ulrik Lund; Tidemand-Lichtenberg, Peter; Buchhave, Preben
2004-01-01
We investigate theoretically the quantum fluctuations of the fundamental field in the output of a nondegenerate second-harmonic generation process occurring inside a laser cavity. Due to the nondegenerate character of the nonlinear medium, a field orthogonal to the laser field is for some operating...... conditions independent of the fluctuations produced by the laser medium. We show that this fact may lead to perfect squeezing for a certain polarization mode of the fundamental field. The experimental feasibility of the system is also discussed....
Entanglement and squeezing in a two-mode system: theory and experiment
International Nuclear Information System (INIS)
Josse, V; Dantan, A; Bramati, A; Giacobino, E
2004-01-01
We report on the generation of non-separable beams produced via the interaction of a linearly polarized beam with a cloud of cold caesium atoms placed in an optical cavity. We convert the squeezing of the two linear polarization modes into quadrature entanglement and show how to find the best entanglement generated in a two-mode system using the inseparability criterion for continuous variables (Duan et al 2000 Phys. Rev. Lett. 84 2722). We verify this method experimentally with a direct measurement of the inseparability using two homodyne detectors. We then map this entanglement into a polarization basis and achieve polarization entanglement
Broadband squeezing of quantum noise in a Michelson interferometer with Twin-Signal-Recycling.
Thüring, André; Gräf, Christian; Vahlbruch, Henning; Mehmet, Moritz; Danzmann, Karsten; Schnabel, Roman
2009-03-15
Twin-Signal-Recycling (TSR) builds on the resonance doublet of two optically coupled cavities and efficiently enhances the sensitivity of an interferometer at a dedicated signal frequency. We report on what we believe to be the first experimental realization of a TSR Michelson interferometer and also its broadband enhancement by squeezed light injection. The complete setup was stably locked, and a broadband quantum noise reduction of the interferometers shot noise by a factor of up to 4 dB was demonstrated. The system was characterized by measuring its quantum noise spectra for several tunings of the TSR cavities. We found good agreement between the experimental results and numerical simulations.
Demonstration of a squeezed-light-enhanced power- and signal-recycled Michelson interferometer.
Vahlbruch, Henning; Chelkowski, Simon; Hage, Boris; Franzen, Alexander; Danzmann, Karsten; Schnabel, Roman
2005-11-18
We report on the experimental combination of three advanced interferometer techniques for gravitational wave detection, namely, power recycling, detuned signal recycling, and squeezed field injection. For the first time, we experimentally prove the compatibility of especially the latter two. To achieve a broadband nonclassical sensitivity improvement, we applied a filter cavity for compensation of quadrature rotation. The signal-to-noise ratio was improved by up to 2.8 dB beyond the coherent state's shot noise. The complete setup was stably locked for arbitrary times and characterized by injected single-sideband modulation fields.
Dalton, B. J.; Goold, J.; Garraway, B. M.; Reid, M. D.
2017-02-01
These two accompanying papers are concerned with entanglement for systems of identical massive bosons and the relationship to spin squeezing and other quantum correlation effects. The main focus is on two mode entanglement, but multi-mode entanglement is also considered. The bosons may be atoms or molecules as in cold quantum gases. The previous paper I dealt with the general features of quantum entanglement and its specific definition in the case of systems of identical bosons. Entanglement is a property shared between two (or more) quantum sub-systems. In defining entanglement for systems of identical massive particles, it was concluded that the single particle states or modes are the most appropriate choice for sub-systems that are distinguishable, that the general quantum states must comply both with the symmetrization principle and the super-selection rules (SSR) that forbid quantum superpositions of states with differing total particle number (global SSR compliance). Further, it was concluded that (in the separable states) quantum superpositions of sub-system states with differing sub-system particle number (local SSR compliance) also do not occur. The present paper II determines possible tests for entanglement based on the treatment of entanglement set out in paper I. Several inequalities involving variances and mean values of operators have been previously proposed as tests for entanglement between two sub-systems. These inequalities generally involve mode annihilation and creation operators and include the inequalities that define spin squeezing. In this paper, spin squeezing criteria for two mode systems are examined, and spin squeezing is also considered for principle spin operator components where the covariance matrix is diagonal. The proof, which is based on our SSR compliant approach shows that the presence of spin squeezing in any one of the spin components requires entanglement of the relevant pair of modes. A simple Bloch vector test for
Comparative Study of Entanglement and Wigner Function for Multi-Qubit GHZ-Squeezed State
Siyouri, Fatima-Zahra
2017-12-01
In this paper we address the possibility of using the Wigner function to capture the quantum entanglement present in a multi-qubit system. For that purpose, we calculate both the degree of entanglement and the Wigner function for mixed tripartite squeezed states of Greenberger-Horne-Zeilinger (GHZ) type then we compare their behaviors. We show that the role of Wigner function in detecting and quantifying bipartite quantum correlation [Int. J. Mod. Phys. B 30 (2016) 1650187] may be generalized to the multipartite case.
Noise suppression in an atomic system under the action of a field in a squeezed coherent state
International Nuclear Information System (INIS)
Gelman, A. I.; Mironov, V. A.
2010-01-01
The interaction of a quantized electromagnetic field in a squeezed coherent state with a three-level Λ-atom is studied numerically by the quantum Monte Carlo method and analytically by the Heisenberg-Langevin method in the regime of electromagnetically induced transparency (EIT). The possibility of noise suppression in the atomic system through the quantum properties of squeezed light is considered in detail; the characteristics of the atomic system responsible for the relaxation processes and noise in the EIT band have been found. Further applications of the Monte Carlo method and the developed numerical code to the study of more complex systems are discussed.
Geotechnical conditions at the Konrad mine. Excavation of drifts and rooms in squeezing rock
International Nuclear Information System (INIS)
Stahlmann, Joachim; Missal, Christian
2014-01-01
The Konrad mine is a former iron ore mine near Salzgitter in Germany. The mine will be rebuilt in the next few years into a repository for low and intermediate level radioactive waste. During this conversion drifts and rooms for operating the repository are extended and newly constructed at shaft 2 on the 2nd floor level (depth 850 m). The planned useful life for the rooms is 40 years. In this period, maintenance-free operation has to be ensured. The bedrock is characterized by complex geology. In addition, the mudstone layers show partly a squeezing behavior. For the proof of stability and usability, the observation method is applied. Therefore numerical prediction models are necessary, which can reproduce the three dimensional stress redistribution and convergences in the rock mass. These numerical calculations are flanked by an extensive geotechnical measurement program in order to detect the real behavior of the bedrock. The underground support system consists of a slotted lining with sliding anchors in the areas where squeezing rock is present. This allows converging of the bedrock. During the convergence period a bearing ring is formed within the rock mass. Afterwards the final lining is created in reinforced shotcrete. One major issue is the assessment of the convergence period taking into account the numerical prediction model and the measurement program.
International Nuclear Information System (INIS)
Sen, Biswajit; Mandal, Swapan
2007-01-01
An initially prepared coherent state coupled to a second-order nonlinear medium is responsible for stimulated and spontaneous hyper Raman processes. By using an intuitive approach based on perturbation theory, the Hamiltonian corresponding to the hyper Raman processes is analytically solved to obtain the temporal development of the field operators. It is true that these analytical solutions are valid for small coupling constants. However, the interesting part is that these solutions are valid for reasonably large time. Hence, the present analytical solutions are quite general and are fresh compared to those solutions under short-time approximations. By exploiting the analytical solutions of field operators for various modes, we investigate the squeezing, photon antibunching and nonclassical photon statistics for pure modes of the input coherent light responsible for hyper Raman processes. At least in one instance (stimulated hyper Raman processes for vibration phonon mode), we report the simultaneous appearance of classical (photon bunching) and nonclassical (squeezing) effects of the radiation field responsible for hyper Raman processes
Elastic contact mechanics: percolation of the contact area and fluid squeeze-out.
Persson, B N J; Prodanov, N; Krick, B A; Rodriguez, N; Mulakaluri, N; Sawyer, W G; Mangiagalli, P
2012-01-01
The dynamics of fluid flow at the interface between elastic solids with rough surfaces depends sensitively on the area of real contact, in particular close to the percolation threshold, where an irregular network of narrow flow channels prevails. In this paper, numerical simulation and experimental results for the contact between elastic solids with isotropic and anisotropic surface roughness are compared with the predictions of a theory based on the Persson contact mechanics theory and the Bruggeman effective medium theory. The theory predictions are in good agreement with the experimental and numerical simulation results and the (small) deviation can be understood as a finite-size effect. The fluid squeeze-out at the interface between elastic solids with randomly rough surfaces is studied. We present results for such high contact pressures that the area of real contact percolates, giving rise to sealed-off domains with pressurized fluid at the interface. The theoretical predictions are compared to experimental data for a simple model system (a rubber block squeezed against a flat glass plate), and for prefilled syringes, where the rubber plunger stopper is lubricated by a high-viscosity silicon oil to ensure functionality of the delivery device. For the latter system we compare the breakloose (or static) friction, as a function of the time of stationary contact, to the theory prediction.
Simulating squeeze flows in multiaxial laminates using an improved TIF model
Ibañez, R.; Abisset-Chavanne, Emmanuelle; Chinesta, Francisco
2017-10-01
Thermoplastic composites are widely considered in structural parts. In this paper attention is paid to squeeze flow of continuous fiber laminates. In the case of unidirectional prepregs, the ply constitutive equation is modeled as a transversally isotropic fluid, that must satisfy both the fiber inextensibility as well as the fluid incompressibility. When laminate is squeezed the flow kinematics exhibits a complex dependency along the laminate thickness requiring a detailed velocity description through the thickness. In a former work the solution making use of an in-plane-out-of-plane separated representation within the PGD - Poper Generalized Decomposition - framework was successfully accomplished when both kinematic constraints (inextensibility and in-compressibility) were introduced using a penalty formulation for circumventing the LBB constraints. However, such a formulation makes difficult the calculation on fiber tractions and compression forces, the last required in rheological characterizations. In this paper the former penalty formulation is substituted by a mixed formulation that makes use of two Lagrange multipliers, while addressing the LBB stability conditions within the separated representation framework, questions never until now addressed.
Directory of Open Access Journals (Sweden)
Patel G.C.M.
2016-09-01
Full Text Available The near net shaped manufacturing ability of squeeze casting process requiresto set the process variable combinations at their optimal levels to obtain both aesthetic appearance and internal soundness of the cast parts. The aesthetic and internal soundness of cast parts deal with surface roughness and tensile strength those can readily put the part in service without the requirement of costly secondary manufacturing processes (like polishing, shot blasting, plating, hear treatment etc.. It is difficult to determine the levels of the process variable (that is, pressure duration, squeeze pressure, pouring temperature and die temperature combinations for extreme values of the responses (that is, surface roughness, yield strength and ultimate tensile strength due to conflicting requirements. In the present manuscript, three population based search and optimization methods, namely genetic algorithm (GA, particle swarm optimization (PSO and multi-objective particle swarm optimization based on crowding distance (MOPSO-CD methods have been used to optimize multiple outputs simultaneously. Further, validation test has been conducted for the optimal casting conditions suggested by GA, PSO and MOPSO-CD. The results showed that PSO outperformed GA with regard to computation time.
Kim, Sue Min; Cook, Kyung Hoon; Lee, Il Jae; Park, Dong Ha; Park, Myong Chul
2017-04-01
In our hospital, an adverse event reporting system was initiated that alerts the plastic surgery department immediately after suspecting contrast media extravasation injury. This system is particularly important for a large volume of extravasation during power injector use. Between March 2011 and May 2015, a retrospective chart review was performed on all patients experiencing contrast media extravasation while being treated at our hospital. Immediate treatment by squeezing with multiple slit incisions was conducted for a portion of these patients. Eighty cases of extravasation were reported from approximately 218 000 computed tomography scans. The expected extravasation volume was larger than 50 ml, or severe pressure was felt on the affected limb in 23 patients. They were treated with multiple slit incisions followed by squeezing. Oedema of the affected limb disappeared after 1-2 hours after treatment, and the skin incisions healed within a week. We propose a set of guidelines for the initial management of contrast media extravasation injuries for a timely intervention. For large-volume extravasation cases, immediate management with multiple slit incisions is safe and effective in reducing the swelling quickly, preventing patient discomfort and decreasing skin and soft tissue problems. © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd.
First demonstration with beam of the achromatic telescoping squeezing (ATS) scheme
International Nuclear Information System (INIS)
Fartoukh, S.
2012-01-01
The Achromatic Telescopic Squeezing (ATS) scheme is a novel squeezing mechanism which is (almost fully) compatible with the existing hardware of the LHC, and enables both the production and the chromatic correction of very low β*. The basic principles of the ATS scheme will be reviewed together with its basic motivation which is to deliver a very ambitious β* of 10-15 cm in view of the even more ambitious performance commitments taken by the HL-LHC project. In this context, a few dedicated beam experiments were meticulously prepared and took place at the LHC in 2011. The results obtained will be highlighted, demonstrating already the viability of the scheme. The plans for 2012 will be discussed, with a few optics considerations which could already justify the implementation of the ATS scheme in the nominal machine, depending on which β* limits will be met first, and that the ATS can solve (e.g. optics compatibility, chromatic aberrations) and obviously cannot: the aperture of the existing triplet. (author)
Noise squeezing of fields that bichromatically excite atoms in a cavity.
Li, Lingchao; Hu, Xiangming; Rao, Shi; Xu, Jun
2016-11-14
It is well known that bichromatic excitation on one common transition can tune the emission or absorption spectra of atoms due to the modulation frequency dependent non-linearities. However little attention has been focused on the quantum dynamics of fields under bichromatic excitation. Here we present dissipative effects on noise correlations of fields in bichromatic interactions with atoms in cavities. We first consider an ensemble of two-level atoms that interacts with the two cavity fields of different frequencies and considerable amplitudes. By transferring the atom-field nonlinearities to the dressed atoms we separate out the dissipative interactions of Bogoliubov modes with the dressed atoms. The Bogoliubov mode dissipation establishes stable two-photon processes of two involved fields and therefore leads to two-mode squeezing. As a generalization, we then consider an ensemble of three-level Λ atoms for cascade bichromatic interactions. We extract the Bogoliubov-like four-mode interactions, which establish a quadrilateral of the two-photon processes of four involved fields and thus result in four-mode squeezing.
Cosmological evolution as squeezing: a toy model for group field cosmology
Adjei, Eugene; Gielen, Steffen; Wieland, Wolfgang
2018-05-01
We present a simple model of quantum cosmology based on the group field theory (GFT) approach to quantum gravity. The model is formulated on a subspace of the GFT Fock space for the quanta of geometry, with a fixed volume per quantum. In this Hilbert space, cosmological expansion corresponds to the generation of new quanta. Our main insight is that the evolution of a flat Friedmann–Lemaître–Robertson–Walker universe with a massless scalar field can be described on this Hilbert space as squeezing, familiar from quantum optics. As in GFT cosmology, we find that the three-volume satisfies an effective Friedmann equation similar to the one of loop quantum cosmology, connecting the classical contracting and expanding solutions by a quantum bounce. The only free parameter in the model is identified with Newton’s constant. We also comment on the possible topological interpretation of our squeezed states. This paper can serve as an introduction into the main ideas of GFT cosmology without requiring the full GFT formalism; our results can also motivate new developments in GFT and its cosmological application.
A new 6-axis apparatus to squeeze the Kawai-cell of sintered diamond cubes
Ito, Eiji; Katsura, Tomoo; Yamazaki, Daisuke; Yoneda, Akira; Tado, Masashi; Ochi, Takahiro; Nishibara, Eiichi; Nakamura, Akihiro
2009-05-01
In order to overcome disadvantages of the DIA type press in squeezing the Kawai-cell, such as uneven compression between the upper and lower anvils and the four surrounding anvils and frictional loss of applied load in the guide block, we have developed a new 6-axis apparatus in which the movements of the six anvils are controlled by a servo mechanism. It is possible to keep the Kawai-cell cubic within an accuracy of ±2 μm during compression and decompression. Pressure generation using sintered diamond cubic anvils with edge length of 14.0 mm and a truncation of 1.5 mm has been carried out up to ca. 60 GPa by measuring electrical resistance of GaP, Zr, and Fe 2O 3. The results are compared with our previous calibration, carried out using an almost the same sample setup for identical anvils at SPring-8, by means of in situ X-ray observation. It is demonstrated that a significant amount of the applied load is lost by friction when the Kawai-cell is squeezed in the DIA type press. The load loss increases with increasing load, or pressure, and amounts to 45% at ca. 60 GPa. Therefore the 6-axis apparatus is very advantageous to generate higher pressures in the Kawai-cell. However, individual control of the anvils sometimes induces a runaway advancement of the anvils which brings about an abrupt increase of pressure.
Egyptian diatomite as high fluid loss squeeze slurry in sealing fractures and
Directory of Open Access Journals (Sweden)
A.M. Al-Sabagh
2016-09-01
Full Text Available Lost circulation is the most costly mud related drilling problem, and induced fracture. Water slurry of diatomite is used as the high fluid loss squeeze slurry in the treatment of lost circulation and in decreasing fluid loss. Egypt has diatomite deposits, especially in El-Fayuom Depression. Fourteen samples were collected from Qasr El-Sagha at the northern shore of Birket Qarun. Samples were examined to identify the diatom species then subjected to X-ray fluorescence, XRD and grain size distribution tests. A total of 38 species related to 13 diatom genera were identified. Cocconeis, Epithemia and Rhopalodia were the predominant genera. The diatomaceous earth which acts as a filter aid material was tested with different additives; bentonite, lime, finely divided paper, polymer, barite and different concentrations with different types of lost circulation materials (LCM to form a high fluid loss squeeze slurry. As a result the required time for collecting the filtrate was decreased to be in the range of 50 s to 1 min and 49 s comparing with the international standard which recommended the filtrate should be collected maximum within 2–3 min.
Identification of specific microorganisms in fresh squeezed street vended fruit juices
Directory of Open Access Journals (Sweden)
K Sahithi Reddy
2016-01-01
Full Text Available Introduction: In developing country like India, street foods such as salads and fresh cut fruits are widely consumed. Among all street foods, fruit juices are common beverages, consumed more because of higher consumer preference both in terms of taste and health. Moreover, there is a dearth of Indian studies on contamination of street vended fruit juices. Aim: To determine the pH and specific microorganisms in freshly squeezed street vended fruit juices. Materials and Methods: Four fruit juices i.e., Grapes, Sweet Lime, Pineapple and Sapota were chosen for the study. Juices were collected in summer season in months between April and June 2013. Ten samples of 50 ml each fruit juice was collected in sterile bottles from various street vendors of Dilshuknagar area of Hyderabad city. Transportation of samples to Food Toxicology laboratory, National Institute of Nutrition was done in the ice box and processing was done within 2–4 h. Results: All juices showed bacterial contamination except one sample of grape juice. Pineapple juice samples showed the high bacterial contamination with all samples positive for fecal coliforms and Shigella spp. (100%. Salmonella spp. was detected only in one sample of Sapota juice (10%. Significant difference among fruit juices for prevalence of microorganisms was seen only for Escherichia coli (P = 0.03 with least count in Grape juice (20%. Conclusion: Freshly squeezed street vended fruit juices were contaminated with pathogenic bacteria, which significantly attributed to public health problem.
Hydromagnetic instability in a stellarator
Energy Technology Data Exchange (ETDEWEB)
Kruskal, M D; Gottlieb, M B; Johnson, J L; Goldman, L M [Project Matterhorn, Princeton University, Princeton, NJ (United States)
1958-07-01
It was noted that when there is a uniform externally imposed longitudinal field much larger than the field of the discharge current, one should expect instabilities in the form of a lateral displacement of the plasma column into a helix of large pitch. At the wavelength of fastest growth the e-folding time approximates the time it takes a sound wave in the plasma to traverse the radius of the plasma column. This problem has been re-examines under the conditions which might be expected to occur in the stellarator during ohmic heating, including the presence of external conductors. The theory is applied to the stellarator; and it is shown that the external conductors are in fact unimportant. The important effects due to the finite length of the Machine are discussed and the effects of more general current distributions are considered. The results from the experiments are given.
Li, Xi-Zeng; Su, Bao-Xia
1996-01-01
It is found that the field of the combined mode of the probe wave and the phase-conjugate wave in the process of non-degenerate four-wave mixing exhibits higher-order squeezing to all even orders. And the generalized uncertainty relations in this process are also presented.
Effect of atomic noise on optical squeezing via polarization self-rotation in a thermal vapor cell
DEFF Research Database (Denmark)
Hsu, M.T.L.; Hetet, G.; Peng, A.
2006-01-01
The traversal of an elliptically polarized optical field through a thermal vapor cell can give rise to a rotation of its polarization axis. This process, known as polarization self-rotation (PSR), has been suggested as a mechanism for producing squeezed light at atomic transition wavelengths. We ...
International Nuclear Information System (INIS)
Yeh, L.
1992-01-01
The phase-space-picture approach to quantum non-equilibrium statistical mechanics via the characteristic function of infinite- mode squeezed coherent states is introduced. We use quantum Brownian motion as an example to show how this approach provides an interesting geometrical interpretation of quantum non-equilibrium phenomena
Energy Technology Data Exchange (ETDEWEB)
Jordan, M. M.; Lewis, M. [Nalco/Exxon Energy Chemicals Ltd, Aberdeen (United Kingdom); Tomlinson, C. J.; Pritchard, A. R. P. [Enterprise Oil Plc, Aberdeen (United Kingdom)
1998-12-31
Field results from a number of scale squeeze treatments carried out on subsea and platform horizontal wells in the Nelson Field of the North Sea are presented. Scale inhibitor chemicals are reviewed along with factors which influence inhibitor selection for both horizontal and highly deviated wells. Formation brine/inhibitor incompatibility, formation minerals/inhibitor incompatibility, and the potential for sand production and oil-in-water process as a result of these incompatibilities, are discussed. Practical difficulties in squeezing subsea horizontal wells, the use of chemical stabilizers to reduce formation brine/inhibitor incompatibility, variation of pump rates to encourage propagation of inhibitor along the wellbore, and the potential of fluid diversion are outlined, stressing the significance of production logging data (or good reservoir simulation data), to evaluate the location of water production prior to the squeeze treatment. Results of these treatments show that with the correct laboratory evaluation of both scale inhibitor and divertor agents, and with appropriate utilization of production logging or reservoir simulation data, it is possible to carry out scale inhibitor squeeze treatments of subsea and platform horizontal wells without having to resort to coiled tubing. 22 refs., 1 tab., 14 figs
DEFF Research Database (Denmark)
Petersen, Marianne Graves
2007-01-01
Squeeze is a multi-person, flexible and interactive furniture that allows for collective and playful exploration of the family history among co-located people in homes. It is designed to explore how we can use digital technology to create settings where co-located family members can collectively ...
International Nuclear Information System (INIS)
Yong Gaochan; Li Baoan; Chen Liewen
2007-01-01
Within a transport model it is shown that the neutron/proton ratio of squeezed-out nucleons perpendicular to the reaction plane, especially at high transverse momenta, in heavy-ion reactions induced by high energy neutron-rich nuclei can be a useful tool for studying the high density behavior of the nuclear symmetry energy
International Nuclear Information System (INIS)
Ben-Aryeh, Y.
2011-01-01
The possibility of using squeezed states and balanced homodyne detection of optical signals in a Michelson interferometer is discussed. The present analysis describes photon statistics measurements effects related to quadrature balanced homodyne detection showing the advantage of using this scheme for detecting weak optical signals.
International Nuclear Information System (INIS)
Han, G.M.; Han, Z.Q.; Luo, A.A.; Liu, B.C.
2015-01-01
Highlights: • Characterization of three-dimensional morphologies of precipitates using AFM. • Quantitative microstructure of aged squeeze-cast AZ91 alloy. • The non-uniform continuous precipitation during aging of squeeze-cast AZ91 alloy. • The relationship between microstructure and property of aged squeeze-cast AZ91 alloy. - Abstract: Quantitative microstructure information is critical to modeling and prediction of mechanical properties of structural components. In this study, the microstructure characteristics of aged squeeze-cast AZ91 alloy were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) analyses. Particularly, a study of the three-dimensional morphology of continuous precipitation during heat treatment was carried out using a combination of TEM and AFM. The results showed that a typical precipitate consisted of three kinds of faces, namely, broad, side, and end faces. The precipitate also presented a lath-shaped morphology with lozenge ends. Combined SEM and TEM analyses revealed quantitative information on the sizes and area number densities of precipitates after aging at different temperatures with different times. In general, the length and width of precipitates increased more rapidly than thickness during aging. The area number density initially increased and then slowly decreased because of coarsening. Furthermore, a special microstructure characteristic of the non-uniform continuous precipitation during aging was investigated using electron probe microanalysis (EPMA). The relationship between hardness response and yield strength was established
Borchert, Sinéad M.; Osland, Michael J.; Enwright, Nicholas M.; Griffith, Kereen
2018-01-01
Coastal wetland ecosystems are expected to migrate landwards in response to rising seas. However, due to differences in topography and coastal urbanization, estuaries vary in their ability to accommodate migration. Low‐lying urban areas can constrain migration and lead to wetland loss (i.e. coastal squeeze), especially where existing wetlands cannot keep pace with rising seas via vertical adjustments. In many estuaries, there is a pressing need to identify landward migration corridors and better quantify the potential for landward migration and coastal squeeze.We quantified and compared the area available for landward migration of tidal saline wetlands and the area where urban development is expected to prevent migration for 39 estuaries along the wetland‐rich USA Gulf of Mexico coast. We did so under three sea level rise scenarios (0.5, 1.0, and 1.5 m by 2100).Within the region, the potential for wetland migration is highest within certain estuaries in Louisiana and southern Florida (e.g. Atchafalaya/Vermilion Bays, Mermentau River, Barataria Bay, and the North and South Ten Thousand Islands estuaries).The potential for coastal squeeze is highest in estuaries containing major metropolitan areas that extend into low‐lying lands. The Charlotte Harbor, Tampa Bay, and Crystal‐Pithlachascotee estuaries (Florida) have the highest amounts of urban land expected to constrain wetland migration. Urban barriers to migration are also high in the Galveston Bay (Texas) and Atchafalaya/Vermilion Bays (Louisiana) estuaries.Synthesis and applications. Coastal wetlands provide many ecosystem services that benefit human health and well‐being, including shoreline protection and fish and wildlife habitat. As the rate of sea level rise accelerates in response to climate change, coastal wetland resources could be lost in areas that lack space for landward migration. Migration corridors are particularly important in highly urbanized estuaries where, due to low‐lying coastal
Aleman, Monica; Weich, Kalie M; Madigan, John E
2017-09-05
Horses are a precocious species that must accomplish several milestones that are critical to survival in the immediate post-birth period for their survival. One essential milestone is the successful transition from the intrauterine unconsciousness to an extrauterine state of consciousness or awareness. This transition involves a complex withdrawal of consciousness inhibitors and an increase in neuroactivating factors that support awareness. This process involves neuroactive hormones as well as inputs related to factors such as cold, visual, olfactory, and auditory stimuli. One factor not previously considered in this birth transition is a yet unreported direct neural reflex response to labor-induced physical compression of the fetus in the birth canal (squeezing). Neonatal maladjustment syndrome (NMS) is a disorder of the newborn foal characterized by altered behavior, low affinity for the mare, poor awareness of the environment, failure to bond to the mother, abnormal sucking, and other neurologically-based abnormalities. This syndrome has been associated with altered events during birth, and was believed to be caused exclusively by hypoxia and ischemia. However, recent findings revealed an association of the NMS syndrome with the persistence of high concentrations of in utero neuromodulating hormones (neurosteroids) in the postnatal period. Anecdotal evidence demonstrated that a novel physical compression (squeeze) method that applies 20 min of sustained pressure to the thorax of some neonatal foals with this syndrome might rapidly hasten recovery. This survey provides information about outcomes and time frames to recovery comparing neonatal foals that were given this squeeze treatment to foals treated with routine medical therapy alone. Results revealed that the squeeze procedure, when applied for 20 min, resulted in a faster full recovery of some foals diagnosed with NMS. The adjunctive use of a non-invasive squeeze method may improve animal welfare by
Energy Technology Data Exchange (ETDEWEB)
Lee, Jae A; Kwak, Hyo Sung; Han, Young Min; Yu, Hee Chul [Chonbuk National University Medical School, Jeonju (Korea, Republic of)
2011-05-15
The effectiveness of the calf-squeeze technique during aspiration thrombectomy using guiding catheter in the treatment of an acute lower extremity deep vein thrombosis (DVT) was evaluated by the use of imaging and the clinical follow-up of patients. A prospective analysis of ten patients (seven women, three men; median age, 56.9 years) with common iliac vein (CIV) obstruction and ipsilateral DVT was performed for this study. All patients presented with leg edema or pain and were treated with catheter-directed thrombolysis via an ipsilateral popliteal vein approach after insertion of a temporary inferior vena cava (IVC) filter. Subsequently, the patients were treated with by aspiration thrombectomy using a guiding catheter to remove the residual thrombus. The calf-squeeze technique during aspiration thrombectomy can be used to induce the proximal migration of thrombi in the popliteal, tibial, and muscular veins were used to increase venous flow. The calf-squeeze technique was employed at mean of 1.3 times (range, 1-3 times). All patients showed proximal migration of a popliteal and muscular vein thrombus during the execution of the calf-squeeze technique. Successful recanalization was achieved in all patients (100%) without any complications. On duplex ultrasonography, which was performed immediately after the aspiration thrombectomy, four patients had a residual thrombus in the soleal muscular veins. However, none of the patients had a thrombus in the popliteal and tibial veins; and, during follow-up, no DVT recurred in any patient. The use of the calf-squeeze technique during aspiration thrombectomy after catheter-directed thrombolysis can induce the proximal migration of thrombi in the popliotibial and muscular veins and is an effective method that can remove a thrombus in calf veins.
International Nuclear Information System (INIS)
Lee, Jae A; Kwak, Hyo Sung; Han, Young Min; Yu, Hee Chul
2011-01-01
The effectiveness of the calf-squeeze technique during aspiration thrombectomy using guiding catheter in the treatment of an acute lower extremity deep vein thrombosis (DVT) was evaluated by the use of imaging and the clinical follow-up of patients. A prospective analysis of ten patients (seven women, three men; median age, 56.9 years) with common iliac vein (CIV) obstruction and ipsilateral DVT was performed for this study. All patients presented with leg edema or pain and were treated with catheter-directed thrombolysis via an ipsilateral popliteal vein approach after insertion of a temporary inferior vena cava (IVC) filter. Subsequently, the patients were treated with by aspiration thrombectomy using a guiding catheter to remove the residual thrombus. The calf-squeeze technique during aspiration thrombectomy can be used to induce the proximal migration of thrombi in the popliteal, tibial, and muscular veins were used to increase venous flow. The calf-squeeze technique was employed at mean of 1.3 times (range, 1-3 times). All patients showed proximal migration of a popliteal and muscular vein thrombus during the execution of the calf-squeeze technique. Successful recanalization was achieved in all patients (100%) without any complications. On duplex ultrasonography, which was performed immediately after the aspiration thrombectomy, four patients had a residual thrombus in the soleal muscular veins. However, none of the patients had a thrombus in the popliteal and tibial veins; and, during follow-up, no DVT recurred in any patient. The use of the calf-squeeze technique during aspiration thrombectomy after catheter-directed thrombolysis can induce the proximal migration of thrombi in the popliotibial and muscular veins and is an effective method that can remove a thrombus in calf veins.
Squeeze-out of nuclear matter as a function of projectile energy and mass
International Nuclear Information System (INIS)
Gutbrod, H.H.; Kampert, K.H.; Kolb, B.; Poskanzer, A.M.; Ritter, H.G.; Schicker, R.; Schmidt, H.R.
1990-01-01
Squeeze-out, a component of the collective flow of nuclear matter, is the preferential emission of particles out of the reaction plane. Using the sphericity method the out-of-plane/in-plane ratio of the kinetic energy flow has been analyzed as a function of multiplicity and beam energy for Ca+Ca, Nb+Nb, and Au+Au collisions measured with the Plastic Ball detector at the Bevalac. Also, azimuthal distribution of the particles around the flow axis are presented together with the extracted out-of-plane/in-plane ratios. Finally, the rapidity dependence of the out-of-plane/in-plane ratio has been investigated with a new method using the transverse momentum components of the particles
Would one rather store squeezing or entanglement in continuous variable quantum memories?
International Nuclear Information System (INIS)
Yadsan-Appleby, Hulya; Serafini, Alessio
2011-01-01
Given two quantum memories for continuous variables and the possibility to perform passive optical operations on the optical modes before or after the storage, two possible scenarios arise resulting in generally different degrees of final entanglement. Namely, one could either store an entangled state and retrieve it directly from the memory, or rather store two separate single-mode squeezed states and then combine them with a beam-splitter to generate the final entangled state. In this Letter, we analytically determine which of the two options yields more entanglement for several regions of the system's parameters, and quantify the advantage it entails. - Highlights: → We study the optimised storage of continuous variable entanglement. → Analytical conditions to determine optimal storage schemes. → Comprehensive numerical studies complementing the analytics. → Specific discussion concerning QND feedback memories included. → Results applicable to very general Gaussian channel.
Quantum squeezed light for probing mitochondrial membranes and study of neuroprotectants
International Nuclear Information System (INIS)
Gourley, Paul Lee; Copeland, Robert Guild; McDonald, Anthony Eugene; Hendricks, Judy K.; Naviaux, Robert K.
2005-01-01
We report a new nanolaser technique for measuring characteristics of human mitochondria. Because mitochondria are so small, it has been difficult to study large populations using standard light microscope or flow cytometry techniques. We recently discovered a nano-optical transduction method for high-speed analysis of submicron organelles that is well suited to mitochondrial studies. This ultrasensitive detection technique uses nano-squeezing of light into photon modes imposed by the ultrasmall organelle dimensions in a semiconductor biocavity laser. In this paper, we use the method to study the lasing spectra of normal and diseased mitochondria. We find that the diseased mitochondria exhibit larger physical diameter and standard deviation. This morphological differences are also revealed in the lasing spectra. The diseased specimens have a larger spectral linewidth than the normal, and have more variability in their statistical distributions
Photon statistical properties of photon-added two-mode squeezed coherent states
International Nuclear Information System (INIS)
Xu Xue-Fen; Wang Shuai; Tang Bin
2014-01-01
We investigate photon statistical properties of the multiple-photon-added two-mode squeezed coherent states (PA-TMSCS). We find that the photon statistical properties are sensitive to the compound phase involved in the TMSCS. Our numerical analyses show that the photon addition can enhance the cross-correlation and anti-bunching effects of the PA-TMSCS. Compared with that of the TMSCS, the photon number distribution of the PA-TMSCS is modulated by a factor that is a monotonically increasing function of the numbers of adding photons to each mode; further, that the photon addition essentially shifts the photon number distribution. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Chater, Nick; Christiansen, Morten H
2016-01-01
If human language must be squeezed through a narrow cognitive bottleneck, what are the implications for language processing, acquisition, change, and structure? In our target article, we suggested that the implications are far-reaching and form the basis of an integrated account of many apparently unconnected aspects of language and language processing, as well as suggesting revision of many existing theoretical accounts. With some exceptions, commentators were generally supportive both of the existence of the bottleneck and its potential implications. Many commentators suggested additional theoretical and linguistic nuances and extensions, links with prior work, and relevant computational and neuroscientific considerations; some argued for related but distinct viewpoints; a few, though, felt traditional perspectives were being abandoned too readily. Our response attempts to build on the many suggestions raised by the commentators and to engage constructively with challenges to our approach.
Thermal Radiation Effects on Squeezing Flow Casson Fluid between Parallel Disks
Directory of Open Access Journals (Sweden)
Sheikh Irfanullah Khan
2016-05-01
Full Text Available In this paper, we investigate the thermal radiation effects in a time-dependent two-dimensional flow of a Casson fluid between two parallel disks when upper disk is taken to be impermeable and lower one is porous. Suitable similarity transforms are employed to convert governing partial differential equations into system of ordinary differential equations. Well known Homotopy Analysis Method (HAM is employed to obtain the expressions for velocity and temperature profiles. Effects of different physical parameters such as squeeze number $S$, Prandtl number $Pr$, Eckert number $Ec$ and the dimensionless length on the flow are also discussed with the help of graphs for velocity and temperature coupled with a comprehensive discussions. The skin friction coefficient and local Nusselt number along with convergence of the series solutions obtained by HAM are presented in tabulated form, while numerical solution is obtained by $RK-4$ method and comparison shows an excellent agreement between both the solutions.
Quantum statistics and squeezing for a microwave-driven interacting magnon system.
Haghshenasfard, Zahra; Cottam, Michael G
2017-02-01
Theoretical studies are reported for the statistical properties of a microwave-driven interacting magnon system. Both the magnetic dipole-dipole and the exchange interactions are included and the theory is developed for the case of parallel pumping allowing for the inclusion of the nonlinear processes due to the four-magnon interactions. The method of second quantization is used to transform the total Hamiltonian from spin operators to boson creation and annihilation operators. By using the coherent magnon state representation we have studied the magnon occupation number and the statistical behavior of the system. In particular, it is shown that the nonlinearities introduced by the parallel pumping field and the four-magnon interactions lead to non-classical quantum statistical properties of the system, such as magnon squeezing. Also control of the collapse-and-revival phenomena for the time evolution of the average magnon number is demonstrated by varying the parallel pumping amplitude and the four-magnon coupling.