Search results for "Squeezing"
showing 7 items of 7 documents
Squeezing of Quantum Noise of Motion in a Micromechanical Resonator
2015
A pair of conjugate observables, such as the quadrature amplitudes of harmonic motion, have fundamental fluctuations which are bound by the Heisenberg uncertainty relation. However, in a squeezed quantum state, fluctuations of a quantity can be reduced below the standard quantum limit, at the cost of increased fluctuations of the conjugate variable. Here we prepare a nearly macroscopic moving body, realized as a micromechanical resonator, in a squeezed quantum state. We obtain squeezing of one quadrature amplitude $1.1 \pm 0.4$ dB below the standard quantum limit, thus achieving a long-standing goal of obtaining motional squeezing in a macroscopic object.
Incidence of microorganisms from fresh orange juice processed by squeezing machines
2012
Abstract This study was carried out to evaluate the microbiological quality of orange juice obtained from squeezing machines in foodservice establishments. The samples included fresh squeezed orange juice and juice which is maintained in metal jugs until consumption. According to the European Commission Regulation (No. 2073/2005 and No. 1441/2007) and Spanish microbiological criteria (No. 3484/2000), 12% and 43% of the total examined lots exceed the adopted limits of mesophilic aerobic counts and Enterobacteriaceae, respectively. Possibly, this contamination is caused by incorrect handling of oranges and juices and also by inadequate cleaning and sanitization of squeezing machine and metal …
Squeezing in Kerr-like cavities: optomechanics, polariton microcavities and superconducting circuits
2017
Aquesta tesi està dedicada fonamentalment a l’estudi teòric de la generació d’estats comprimits de la llum mitjançant cavitats òptiques tipus Kerr amb un bombeig bicromàtic. Bàsicament amb aquest tipus d’injecció fem que la usual corba de biestabilitiat observada en la dinàmica no lineal d’aquests sistemes amb injecció monocromàtica, canvie a una bifurcació tipus forca, degut a un fenòmen de mescla de quatre ones. A prop de l’esmentada bifurcació les fluctuacions quàntiques del camp electromagnètic són modificades de forma que l’estat quàntic de la llum a l’eixida de la cavitat és d’un buit comprimit. En aquesta introducció explicarem breument que és aquesta compressió de la llum, que són l…
Output Field-Quadrature Measurements and Squeezing in Ultrastrong Cavity-QED
2015
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…
Revealing Hidden Quantum Correlations in an Electromechanical Measurement.
2018
Under a strong quantum measurement, the motion of an oscillator is disturbed by the measurement back-action, as required by the Heisenberg uncertainty principle. When a mechanical oscillator is continuously monitored via an electromagnetic cavity, as in a cavity optomechanical measurement, the back-action is manifest by the shot noise of incoming photons that becomes imprinted onto the motion of the oscillator. Following the photons leaving the cavity, the correlations appear as squeezing of quantum noise in the emitted field. Here we observe such "ponderomotive" squeezing in the microwave domain using an electromechanical device made out of a superconducting resonator and a drumhead mechan…
Fluctuacions quàntiques en cavitats òptiques no lineals
2011
Aquesta tesi doctoral tracta sobre alguns aspectes de la generació de llum comprimida en cavitats no lineals tipus Kerr. La llum comprimida és un dels tipus de "llum quàntica", un tipus de llum que posseeix propietats relatives a les fluctuacions en els valors esperats dels seus observables de les què no es pot donar compte si no és mitjançant l'ús de la teoria quàntica de la radiació. L'estat buit del camp electromagnètic posseeix fluctuacions d'acord amb el principi d'incertitud d'Heisenberg. En aquest context, denominem llum comprimida a un tipus de radiació que presenta en algun dels seus observables fluctuacions menors que les corresponents a l'estat buit. Aquest tipus especial de radi…
Increasing the Astrophysical Reach of the Advanced Virgo Detector via the Application of Squeezed Vacuum States of Light
2019
Current interferometric gravitational-wave detectors are limited by quantum noise over a wide range of their measurement bandwidth. One method to overcome the quantum limit is the injection of squeezed vacuum states of light into the interferometer's dark port. Here, we report on the successful application of this quantum technology to improve the shot noise limited sensitivity of the Advanced Virgo gravitational-wave detector. A sensitivity enhancement of up to 3.2±0.1 dB beyond the shot noise limit is achieved. This nonclassical improvement corresponds to a 5%-8% increase of the binary neutron star horizon. The squeezing injection was fully automated and over the first 5 months of the thi…