International Journal of Quantum Information最新文献

{"title":"Freezing of geometric discords for two qutrits in environments","authors":"W. Xiao, Mei-Yun Zhen, Xi-Wen Hou","doi":"10.1142/s0219749922500198","DOIUrl":"https://doi.org/10.1142/s0219749922500198","url":null,"abstract":"","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41349294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Entanglement and mechanical squeezing in dissipative atom-photomechanical hybrid systems","authors":"Xin Wang, Ang Li, Song-Lin Yang, Jian-Song Zhang","doi":"10.1142/s0219749922500186","DOIUrl":"https://doi.org/10.1142/s0219749922500186","url":null,"abstract":"","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48549296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring quantum properties of bipartite mixed states under coherent and incoherent basis","authors":"Sovik Roy, A. Bhattacharjee, C. Radhakrishnan, Md. Manirul Ali, B. Ghosh","doi":"10.1142/S0219749923500107","DOIUrl":"https://doi.org/10.1142/S0219749923500107","url":null,"abstract":"Quantum coherence and quantum entanglement are two different manifestations of the superposition principle. In this article we show that the right choice of basis to be used to estimate coherence is the separable basis. The quantum coherence estimated using the Bell basis does not represent the coherence in the system, since there is a coherence in the system due to the choice of the basis states. We first compute the entanglement and quantum coherence in the two qubit mixed states prepared using the Bell states and one of the states from the computational basis. The quantum coherence is estimated using the l1-norm of coherence, the entanglement is measured using the concurrence and the mixedness is measured using the linear entropy. Then we estimate these quantities in the Bell basis and establish that coherence should be measured only in separable basis, whereas entanglement and mixedness can be measured in any basis. We then calculate the teleportation fidelity of these mixed states and find the regions where the states have a fidelity greater than the classical teleportation fidelity. We also examine the violation of the Bell-CHSH inequality to verify the quantum nonlocal correlations in the system. The estimation of the above mentioned quantum correlations, teleportation fidelity and the verification of Bell-CHSH inequality is also done for bipartite states obtained from the tripartite systems by the tracing out of one of their qubits. We find that for some of these states teleportation is possible even when the Bell-CHSH inequality is not violated, signifying that nonlocality is not a necessary condition for quantum teleportation.","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48257247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparing Maximally Entangled States By Monitoring the Environment-System Interaction","authors":"Ali Abu-Nada, Moataz A. Salhab","doi":"10.1142/s0219749923400087","DOIUrl":"https://doi.org/10.1142/s0219749923400087","url":null,"abstract":"A common assumption in open quantum systems in general is that the noise induced by the environment, due to the continuous interaction between a quantum system and its environment, is responsible for the disappearance of quantum properties of this quantum system. Interestingly, we show that an environment can be engineered and controlled to direct an arbitrary quantum system towards a maximally entangled state and thus can be considered as a resource for quantum information processing. Barreiro et.al. [Nature 470, 486 (2011)] demonstrated this idea experimentally using an open-system quantum simulator up to five trapped ions . In this paper, we direct an arbitrary initial mixed state of two and four qubits, which is interacting with its environment, into a maximally entangled state . We use QASM simulator and also an IBM Q real processor, with and without errors mitigating, to investigate the effect of the noise on the preparation of the initial mixed state of the qubits in addition to the population of the target state.","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43177700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The continuous-time quantum walk on some graphs based on the view of quantum probability","authors":"Qi Han, Yaxin Kou, Ning Bai, Huan Wang","doi":"10.1142/s0219749922500150","DOIUrl":"https://doi.org/10.1142/s0219749922500150","url":null,"abstract":"<p>In this paper, continuous-time quantum walk is discussed based on the view of quantum probability, i.e. the quantum decomposition of the adjacency matrix <i>A</i> of graph. Regard adjacency matrix <i>A</i> as Hamiltonian which is a real symmetric matrix with elements 0 or 1, so we regard <span><math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo><mi>i</mi><mi>t</mi><mi>A</mi></mrow></msup></math></span><span></span> as an unbiased evolution operator, which is related to the calculation of probability amplitude. Combining the quantum decomposition and spectral distribution <span><math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"><mi>μ</mi></math></span><span></span> of adjacency matrix <i>A</i>, we calculate the probability amplitude reaching each stratum in continuous-time quantum walk on complete bipartite graphs, finite two-dimensional lattices, binary tree, <span><math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"><mi>N</mi></math></span><span></span>-ary tree and <span><math altimg=\"eq-00004.gif\" display=\"inline\" overflow=\"scroll\"><mi>N</mi></math></span><span></span>-fold star power <span><math altimg=\"eq-00005.gif\" display=\"inline\" overflow=\"scroll\"><msup><mrow><mi>G</mi></mrow><mrow><mo>⋆</mo><mi>N</mi></mrow></msup></math></span><span></span>. Of course, this method is also suitable for studying some other graphs, such as growing graphs, hypercube graphs and so on, in addition, the applicability of this method is also explained.</p>","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":"169 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138503676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Channel-based coherence of quantum states","authors":"Cheng-Yang Zhang, Pu Wang, Li-Hua Bai, Zhi-Hua Guo, Huai-Xin Cao","doi":"10.1142/s0219749922500149","DOIUrl":"https://doi.org/10.1142/s0219749922500149","url":null,"abstract":"&lt;p&gt;Quantum coherence is one of the most fundamental and striking features in quantum physics. Considered the standard coherence (SC), the partial coherence (PC) and the block coherence (BC) as variance of quantum states under some quantum channels (QCs) &lt;span&gt;&lt;math altimg=\"eq-00001.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, we propose the concept of channel-based coherence of quantum states, called &lt;span&gt;&lt;math altimg=\"eq-00002.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-coherence for short, which contains the SC, PC and BC, but does not contain the positive operator-valued measure (POVM)-based coherence. By our definition, a state &lt;span&gt;&lt;math altimg=\"eq-00003.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi&gt;ρ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; is said to be &lt;span&gt;&lt;math altimg=\"eq-00004.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-incoherent if it is a fixed point of a QC &lt;span&gt;&lt;math altimg=\"eq-00005.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;, otherwise, it is said to be &lt;span&gt;&lt;math altimg=\"eq-00006.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-coherent. First, we find the set &lt;span&gt;&lt;math altimg=\"eq-00007.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"cal\"&gt;ℐ&lt;/mi&gt;&lt;mo stretchy=\"false\"&gt;(&lt;/mo&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;mo stretchy=\"false\"&gt;)&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; of all &lt;span&gt;&lt;math altimg=\"eq-00008.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-incoherent states for some given channels &lt;span&gt;&lt;math altimg=\"eq-00009.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; and prove that the set &lt;span&gt;&lt;math altimg=\"eq-00010.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"cal\"&gt;ℐ&lt;/mi&gt;&lt;mo stretchy=\"false\"&gt;(&lt;/mo&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;mo stretchy=\"false\"&gt;)&lt;/mo&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt; forms a nonempty compact convex set for any channel &lt;span&gt;&lt;math altimg=\"eq-00011.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;. Second, we define &lt;span&gt;&lt;math altimg=\"eq-00012.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-incoherent operations (&lt;span&gt;&lt;math altimg=\"eq-00013.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-IOs) and prove that the set of all &lt;span&gt;&lt;math altimg=\"eq-00014.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-IOs is a nonempty convex set. We also establish some characterizations of a &lt;span&gt;&lt;math altimg=\"eq-00015.gif\" display=\"inline\" overflow=\"scroll\"&gt;&lt;mi mathvariant=\"normal\"&gt;Φ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;&lt;span&gt;&lt;/span&gt;-IO in terms of its Kraus operators. Lastly, we ","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":"169 2","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138503675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Localization in quantum walks with periodically arranged coin matrices","authors":"Chusei Kiumi","doi":"10.1142/s0219749922500137","DOIUrl":"https://doi.org/10.1142/s0219749922500137","url":null,"abstract":"<p>There is a property called localization, which is essential for applications of quantum walks. From a mathematical point of view, the occurrence of localization is known to be equivalent to the existence of eigenvalues of the time evolution operators, which are defined by coin matrices. A previous study proposed an approach to the eigenvalue problem for space-inhomogeneous models using transfer matrices. However, the approach was restricted to models whose coin matrices are the same in positions sufficiently far to the left and right, respectively. This study shows that the method can be applied to extended models with periodically arranged coin matrices. Moreover, we investigate localization by performing the eigenvalue analysis and deriving their time-averaged limit distribution.</p>","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":"169 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138503674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Entanglement Quantification Enhanced by Dark Count Correction","authors":"A. Czerwinski","doi":"10.1142/S0219749922500216","DOIUrl":"https://doi.org/10.1142/S0219749922500216","url":null,"abstract":"In this letter, we propose a method of dark count correction in quantum state tomography of entangled photon pairs. The framework is based on a linear model of dark counts, which is imposed on the measurement formalism. The method is tested on empirical data derived from an experiment on polarization-entangled photons. We demonstrate that the numerical approach to dark count correction guarantees more reliable state reconstruction compared with standard estimation. Most importantly, however, the conceptually simple theoretical approach proves to be more efficient at entanglement quantification than experimental techniques.","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49411322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computing the lowest eigenstate of tight-binding Hamiltonians using quantum walks","authors":"Georgios D. Varsamis, Ioannis G. Karafyllidis","doi":"10.1142/s0219749922500125","DOIUrl":"https://doi.org/10.1142/s0219749922500125","url":null,"abstract":"<p>Finding or estimating the lowest eigenstate of quantum system Hamiltonians is an important problem for quantum computing, quantum physics, quantum chemistry, and material science. Several quantum computing approaches have been developed to address this problem. The most frequently used method is variational quantum eigensolver (VQE). Many quantum systems, and especially nanomaterials, are described using tight-binding Hamiltonians, but until now no quantum computation method has been developed to find the lowest eigenvalue of these specific, but very important, Hamiltonians. We address the problem of finding the lowest eigenstate of tight-binding Hamiltonians using quantum walks. Quantum walks is a universal model of quantum computation equivalent to the quantum gate model. Furthermore, quantum walks can be mapped to quantum circuits comprising qubits, quantum registers, and quantum gates and, consequently, executed on quantum computers. In our approach, probability distributions, derived from wave function probability amplitudes, enter our quantum algorithm as potential distributions in the space where the quantum walk evolves. Our results showed the quantum walker localization in the case of the lowest eigenvalue is distinctive and characteristic of this state. Our approach will be a valuable computation tool for studying quantum systems described by tight-binding Hamiltonians.</p>","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":"169 4","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138503673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Passive decoy state phase matching quantum key distribution","authors":"Jiang-ping Zhou, Yuanyuan Zhou, Rui-Wen Gu, Xuejun Zhou","doi":"10.1142/s0219749922500058","DOIUrl":"https://doi.org/10.1142/s0219749922500058","url":null,"abstract":"In this paper, a passive decoy state phase matching quantum key distribution scheme is proposed based on the heralded pair coherent state light source to make the protocol more practical and safe. Without changing the intensity of the light source, we can derive four different data sets by dividing the raw key data into four groups according to the combined results of detectors in source end. The scheme can make use of the different data sets to estimate the parameters and extract the secret key. The key generation rate formula is derived after the parameter estimation. The performance of the proposed scheme is analyzed with and without taking statistical fluctuation into consideration. The simulation results show that compared with the existing active decoy-state method, the proposed passive method has slightly lower key rate when the transmission distance is short, and has obviously higher key rate when the transmission distance exceeds 406[Formula: see text]km. The maximum safety transmission distance of the proposed scheme is 452[Formula: see text]km which is relatively further. According to the influence of statistical fluctuation, the performance of the proposed scheme declines as the length of the data falls. Even though the data size is [Formula: see text], the max safety transmission distance is also more than 400[Formula: see text]km.","PeriodicalId":51058,"journal":{"name":"International Journal of Quantum Information","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48639952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}