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

{"title":"Universal dynamical control of decay and decoherence in multilevel systems","authors":"G. Gordon, G. Kurizki, A. Kofman","doi":"10.1088/1464-4266/7/10/012","DOIUrl":"https://doi.org/10.1088/1464-4266/7/10/012","url":null,"abstract":"A unified theory is presented of dynamically modified decay and decoherence in driven multilevel quantum systems that are weakly coupled to arbitrary zero-temperature reservoirs. Examples of different phase and amplitude modulations are given for two-level systems (qubits). Analysis of modulations on multilevel systems is detailed with a numerical example using quasiperiodic impulsive phase jumps. The merits and disadvantages of the different modulation types are discussed.","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":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/10/012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60911522","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":"Arbitrarily perfect quantum communication using unmodulated spin chains, a collaborative approach","authors":"B. Vaucher, D. Burgarth, S. Bose","doi":"10.1088/1464-4266/7/10/023","DOIUrl":"https://doi.org/10.1088/1464-4266/7/10/023","url":null,"abstract":"We shall consider a quantum communication channel constituted by two open spin chains with nearest neighbour interactions and fixed coupling strengths, connected to several users. Assuming that the users of this quantum data bus can apply simple gates on sites of the chain that they are connected to, we will see that it is possible to gain information on the position of the qubit during the transmission, and to use this information to accelerate the communication process. We will also see that performing frequent measurements on the system affects the dynamics of propagation of quantum information in an interesting way.","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":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/10/023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60912724","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":"Theory of control of the dynamics of the interface between stationary and flying qubits","authors":"W. Yao, Renbao Liu, L. Sham","doi":"10.1088/1464-4266/7/10/016","DOIUrl":"https://doi.org/10.1088/1464-4266/7/10/016","url":null,"abstract":"We present a scheme of control for the arbitrary interplay between a stationary qubit and a flying qubit (carried by a single-photon wavepacket) at a quantum interface composed of a three-level system coupled to a continuum through a cavity. It can be used for generation or reception of an arbitrarily shaped single-photon wavepacket. The generation process can also be controlled to create entanglement between the stationary qubit and flying qubit. The generation and reception operation can be combined to perform quantum network operations such as transfer, swap and entanglement creation for qubits at distant nodes.","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":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/10/016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60912200","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":"Coherence protection by random coding.","authors":"É. Brion, V. Akulin, I. Dumer, G. Harel, G. Kurizki","doi":"10.1088/1464-4266/7/10/022","DOIUrl":"https://doi.org/10.1088/1464-4266/7/10/022","url":null,"abstract":"We show that the multidimensional Zeno effect combined with non-holonomic control allows one to efficiently protect quantum systems from decoherence by a method similar to classical random coding. The method is applicable to arbitrary error-inducing Hamiltonians and general quantum systems. The quantum encoding approaches the Hamming upper bound for large dimension increases. Applicability of the method is demonstrated with a seven-qubit toy computer.","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":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/10/022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60912576","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":"Multiphoton coherent control in complex systems.","authors":"Debabrata Goswami","doi":"10.1088/1464-4266/7/10/009","DOIUrl":"https://doi.org/10.1088/1464-4266/7/10/009","url":null,"abstract":"<p><p>Control of multiphoton transitions is demonstrated for a multilevel system by generalizing the instantaneous phase of any chirped pulse as individual terms of a Taylor series expansion. In the case of a simple two-level system, all odd terms in the series lead to population inversion while the even terms lead to self-induced transparency. The results hold for multiphoton transitions that do not have any lower-order photon resonance or any intermediate virtual state dynamics within the laser pulse width.</p>","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":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/10/009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"26633818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Special issue on quantum control","authors":"S. Mancini, V. Man'ko, H. Wiseman","doi":"10.1088/1464-4266/7/10/E01","DOIUrl":"https://doi.org/10.1088/1464-4266/7/10/E01","url":null,"abstract":"Controlling the dynamics or measurement of quantum systems via the manipulation of external parameters is a most important phenomenon that lies at the heart of several fields including atomic and optical physics, molecular chemistry and quantum information. As quantum technologies have matured, a host of practical applications of quantum control have been realized in quantum optics, cavity QED, atomic spin ensembles, ion trapping, and Bose--Einstein condensation. As a result, quantum control theory is a rapidly growing research field. The aim of this special issue is to give an idea of the present status of research in quantum control, and to stimulate further activity. The papers chosen cover a great variety of ideas in this field. To aid the reader, we have divided the papers into four broad sections: quantum filtering and feedback control; open-loop control; quantum information applications; optical and related applications. Of course there are many papers that cross the boundaries between the categories we have identified, so we encourage readers to peruse the whole issue. While some may quibble with our classification scheme, we think it will be useful, especially to those who are new to the area. In each section the papers are ordered by date of submission. The first section is on quantum filtering and feedback control. Quantum filtering means determining estimates for some (or all) observables of the system from classical measurement results obtained gradually over time from the output of the quantum system. The conditioned quantum state is one way to generate such estimates. This filtering of the measurement results is useful for feedback control (also known as closed-loop control), because those estimates can be used as the basis for varying the external control parameters. This section begins with a review article (the one exception to the ordering of papers by submission date). The second section is on open-loop control in the broad sense. This is concerned with how to drive a quantum system from an initial given state to a pre-determined target state. This includes the question of controllability: whether a controller can drive a quantum system to a desired state, for which the main tools are group theory and graph theory. Quantum optimal control is concerned with finding the best control fields (according to some cost function) to achieve the desired target for a controllable system. Coherent control is a particularly powerful method for guiding the state of a quantum system (typically a molecule) towards the target by applying semiclassical potentials and exploiting quantum interference effects. Another technique is learning control (which can be considered a kind of closed-loop control) in which the experiment is run many times, and each time the output from the sample is used to modify the control fields for the next (independently prepared) sample. The third and fourth sections are devoted more to applications. The third section ","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":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/10/E01","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60913237","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":"The revival–collapse phenomenon in the quadrature field components of the two-mode multiphoton Jaynes–Cummings model","authors":"F. El-orany","doi":"10.1088/1464-4266/7/11/005","DOIUrl":"https://doi.org/10.1088/1464-4266/7/11/005","url":null,"abstract":"In this paper we consider a system consisting of a two-level atom in an excited state interacting with two modes of a radiation field prepared initially in l-photon coherent states. This system is described by a two-mode multiphoton (i.e., k1,k2) Jaynes–Cummings model (JCM). For this system we investigate the occurrence of the revival–collapse phenomenon (RCP) in the evolution of the single-mode, two-mode, sum and difference quadrature squeezing. We show that there is a class of states for which all these types of squeezing exhibit RCP similar to that involved in the corresponding atomic inversion. Also we show numerically that the single-mode squeezing of the first mode for (k1,k2) = (3,1) provides RCP similar to that of the atomic inversion of the case (k1,k2) = (1,1); however, sum and difference squeezing give partial information on that case. Moreover, we show that single-mode, two-mode and sum squeezing for the case (k1,k2) = (2,2) provides information on the atomic inversion of the single-mode two-photon JCM. We derive the rescaled squeezing factors giving accurate information on the atomic inversion for all cases. The consequences of these results are that the homodyne and heterodyne detectors can be used to detect the RCP for the two-mode JCM.","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":"2005-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/11/005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60913283","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":"Optical dipole trapping beyond the rotating wave approximation: the case of large detuning","authors":"V. E. Lembessis, D. Ellinas","doi":"10.1088/1464-4266/7/11/002","DOIUrl":"https://doi.org/10.1088/1464-4266/7/11/002","url":null,"abstract":"We show that the inclusion of counter-rotating terms, usually dropped in evaluations of the interaction of an electric dipole of a two-level atom with the electromagnetic field, leads to significant modifications of the trapping potential in the case of large detuning. The results are shown to be in excellent numerical agreement with recent experimental findings for the case of modes of Laguerre–Gauss spatial profile.","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":"2005-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/11/002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60912985","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":"Quantum teleportation of single-mode thermal state of light field","authors":"Junxiang Zhang, C. Xie, K. Peng","doi":"10.1088/1464-4266/7/11/001","DOIUrl":"https://doi.org/10.1088/1464-4266/7/11/001","url":null,"abstract":"The quantum teleportation of a single-mode thermal state of a light field is discussed using the projection synthesis technique in the Schrodinger picture. The statistical distance (SD) between the teleported input and output states is introduced to evaluate the efficiency of single-mode thermal state teleportation. For a given system and available entanglement, both the SD and classical boundary depend on the mean photon numbers of the teleported thermal light field. The dependences of the SD on the normalized classical gain, EPR (Einstein–Podolsky–Rosen) entanglement and mean photon numbers of the thermal field are calculated.","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":"2005-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/11/001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60912833","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":"Control of photon correlations in type II parametric down-conversion","authors":"R. Andrews, A. T. Joseph, E. Pike, S. Sarkar","doi":"10.1088/1464-4266/7/12/007","DOIUrl":"https://doi.org/10.1088/1464-4266/7/12/007","url":null,"abstract":"In this paper we describe theoretically quantum control of temporal correlations of entangled photons produced by collinear type II spontaneous parametric down-conversion. We examine the effect of spectral phase modulation of the signal or idler photons arriving at a 50/50 beam splitter on the temporal shape of the entangled-photon wavepacket. The coincidence count rate is calculated analytically for photon pairs in terms of the modulation depth applied to either the signal or idler beam with a spectral phase filter. It is found that the two-photon coincidence rate can be controlled by varying the modulation depth of the spectral filter.","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":"2005-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/1464-4266/7/12/007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60914099","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}