Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society最新文献

{"title":"New squeezing operator derived using the bipartite coherent entangled state representation","authors":"H. Fan, Xu-bing Tang","doi":"10.1088/1464-4266/7/12/048","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/048","url":null,"abstract":"Using the newly constructed bipartite coherent entangled state, we derive the corresponding squeezing operators, which have their own squeezing properties, in a natural way. The derivation is based on the method of integration within an ordered product of operators and the completeness relation of the bipartite coherent entangled state.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/048","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60915778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atomic correlations and cavity field decoherence in a strongly driven micromaser","authors":"F. Casagrande, A. Lulli","doi":"10.1088/1464-4266/7/12/002","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/002","url":null,"abstract":"In a micromaser where a classical field strongly drives the atoms while they cross the cavity, remarkable atom–atom correlations show up at steady state, which vanish much faster than dissipative decay. Hence we consider atom pair correlation measurements in which the detection of the first probe atom prepares a mesoscopic superposition state of the cavity field, that entangles with a second probe atom. The conditional probabilities for the latter atomic detection provide a description of the decoherence of the superposition state, occurring in an open system in the presence of pumping, driving, dissipative, and thermal effects. The decoherence rate scales as the squared interaction time, that sets the separation in phase space between the superposition components, whereas the quantum coherence is unaffected by the atomic pumping. Hence we further investigate the system when the cavity is not pumped. Starting the correlation measurements from a thermal state, we can describe the effect of temperature on decoherence. Starting from a vacuum state, the superposition states are maximally separated Schrodinger cat states, whose decoherence can thus be monitored.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60913670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Secure communication with a heralded single-photon source","authors":"A. Trifonov, A. Zavriyev","doi":"10.1088/1464-4266/7/12/050","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/050","url":null,"abstract":"Secure long distance communication over optical fibres requires robust data encryption. While the encryption itself can be conducted using classical algorithms, there is no unconditionally secure method of classical key distribution. Quantum key distribution (QKD), on the other hand, can provide users of the optical networks with unconditionally secure keys. Since QKD is based on single-photon transmission, one of the challenging tasks is to overcome the distance limitation imposed by the losses in optical fibres. In this work we show that single-photon based QKD outperforms the industry-standard weak coherent pulse approach. We also present our recent experimental results on building a heralded single-photon source based on spontaneous parametric down-conversion of CW light and discuss problems and challenges of heralded single-photon generation in the CW regime.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/050","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60915790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simple direct measurement of nonclassical joint signal–idler photon-number statistics and the correlation area of twin photon beams","authors":"O. Haderka, J. Peřina, M. Hamar","doi":"10.1088/1464-4266/7/12/020","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/020","url":null,"abstract":"The measurement of the joint signal–idler photon-number distribution of a field obtained from spontaneous parametric downconversion using an intensified CCD camera is presented. It is shown that a classicality criterion is violated directly by the measured data. Characteristic dimensions of the area of correlation are determined in the same experimental set-up.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60914447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Squeezing generation, revivals and entanglement in a cavity–ion system in contact with a thermal reservoir","authors":"R. Rangel, N. Zagury","doi":"10.1088/1464-4266/7/12/027","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/027","url":null,"abstract":"We consider a system consisting of a single two-level ion in a harmonic trap, which is localized inside an optical cavity in contact with a thermal bath and subjected to the action of two external lasers. We are able to obtain an analytical solution for the total density operator of the system and show that squeezing in the motion of the ion and in the cavity field is generated. We also show that complete revivals of the states of the motion of the ion and of the cavity field occur periodically when the temperature is zero. The correlations and entanglement between the motion and the cavity field are studied. We found that for entanglement may either disappear completely for finite times or disappear and appear during finite intervals.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60914900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"About SIC POVMs and discrete Wigner distributions","authors":"S. Colin, J. Corbett, T. Durt, D. Gross","doi":"10.1088/1464-4266/7/12/051","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/051","url":null,"abstract":"A set of d2 vectors in a Hilbert space of dimension d is called equiangular if each pair of vectors encloses the same angle. The projection operators onto these vectors define a POVM which is distinguished by its high degree of symmetry. Measures of this kind are called symmetric informationally complete, or SIC POVMs for short, and could be applied for quantum state tomography. Despite its simple geometrical description, the problem of constructing SIC POVMs or even proving their existence seems to be very hard. It is our purpose to introduce two applications of discrete Wigner functions to the analysis of the problem at hand. First, we will present a method for identifying symmetries of SIC POVMs under Clifford operations. This constitutes an alternative approach to a structure described before by Zauner and Appleby. Further, a simple and geometrically motivated construction for an SIC POVM in dimensions two and three is given (which, unfortunately, allows no generalization). Even though no new structures are found, we hope that the re-formulation of the problem may prove useful for future inquiries.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/051","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60915850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-dependent quantum damped oscillator with ‘minimal noise’: application to the nonstationary Casimir effect in nonideal cavities","authors":"V. Dodonov","doi":"10.1088/1464-4266/7/12/003","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/003","url":null,"abstract":"We consider a consistent model of a quantum damped harmonic oscillator with arbitrary time-dependent frequency and damping coefficients in the frameworks of the Heisenberg–Langevin equations with two noncommuting delta-correlated noise operators. For the 'minimal noise' set of correlation functions, which have the same time dependence as the damping coefficient, we obtain the exact solution, which is the generalization of Husimi's solution for the undamped nonstationary oscillator. The model is applied to the problem of the photon creation from vacuum or thermal states due to the nonstationary Casimir effect inside the cavity with periodical time-dependent conductivity of the thin semiconductor boundary layer, simulating the periodical displacements of the wall. The general formula for the rate of photon generation under the resonance conditions in the presence of dissipation is obtained.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60913753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonunitary squeezing and biorthogonal scalar products in polarization optics","authors":"Y. Ben-Aryeh","doi":"10.1088/1464-4266/7/12/004","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/004","url":null,"abstract":"The polarization vectors of monochromatic electromagnetic fields can be transformed by multiplying them by 2 ? 2 matrices representing, respectively, retardation plates, rotators and partial polarizers. The present description of partial polarizers is related to a two-dimensional Lorentz algebra SU(1,1) leading to nonunitary squeezing as the present SU(1,1) algebra includes non-Hermitian operators in addition to the Hermitian ones. The present analysis exploits the use of similarity transformations which are more general than the unitary transformations used usually in quantum mechanics. By performing a similarity transformation on a set of Hermitian physical operators the transformed operators are Hermitian with respect to new scalar product defined by the use of a new metric. It is shown that such transformations can be implemented experimentally by the use of polarization optics and the metric obtained in such transformations is analysed.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60913826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Squeeze transformation and optics after Einstein","authors":"Young S. Kim, M. Man'ko, M. Planat","doi":"10.1088/1464-4266/7/12/E01","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/E01","url":null,"abstract":"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 Besancon, 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-electron) statistics and fluctuations of the electromagnetic field, whose importance was first emphasized by Einstein in 1905. The squeezed states can also be considered as a generalization of the concept of coherent states, which turned out to be one of the most important theoretical tools for solving the numerous problems of quantum optics. It seems highly symbolical that the printed version of this special issue will appear in the same month when one of the prominent creators of the theory of coherent states and modern quantum optics—Professor Roy J Glauber—will receive his Nobel Prize in Stockholm. ICSSUR'05 was opened by the invited talk of R J Glauber, `What makes a quantum jump?', and we take great pleasure in congratulating him on this well deserved award. We are sure that all participants of ICSSUR'05 and all readers of this special issue share our feelings. Two other Nobel Prize winners of 2005—Professor J L Hall and Professor T W H\"ansch—also made great contributions to quantum optics. In partic","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/E01","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60915958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards quantum correlated polariton modes in semiconductor microcavities","authors":"M. Romanelli, C. Leyder, J. Karr, A. Baas, E. Giacobino, A. Bramati","doi":"10.1088/1464-4266/7/12/012","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/012","url":null,"abstract":"In planar semiconductor microcavities in the strong coupling regime, nonlinear effects such as a Kerr-like effect, parametric fluorescence and parametric oscillation are observed, as a result of the parametric scattering of polaritons. After discussing the basic physical properties of the system and their theoretical description, we report on our experimental demonstration of polariton squeezing in the degenerate scattering configuration (Kerr configuration), and on the generation of correlated polaritons in the nondegenerate configuration. The latter results open the way to the generation of quantum correlated polariton modes.","PeriodicalId":87441,"journal":{"name":"Journal of optics. B, Quantum and semiclassical optics : journal of the European Optical Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60914342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}