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Variational Amplitude Amplification for Solving QUBO Problems 变分振幅放大求解QUBO问题
Quantum Reports Pub Date : 2023-10-01 DOI: 10.3390/quantum5040041
Daniel Koch, Massimiliano Cutugno, Saahil Patel, Laura Wessing, Paul M. Alsing
{"title":"Variational Amplitude Amplification for Solving QUBO Problems","authors":"Daniel Koch, Massimiliano Cutugno, Saahil Patel, Laura Wessing, Paul M. Alsing","doi":"10.3390/quantum5040041","DOIUrl":"https://doi.org/10.3390/quantum5040041","url":null,"abstract":"We investigate the use of amplitude amplification on the gate-based model of quantum computing as a means for solving combinatorial optimization problems. This study focuses primarily on quadratic unconstrained binary optimization (QUBO) problems, which are well-suited for qubit superposition states. Specifically, we demonstrate circuit designs which encode QUBOs as ‘cost oracle’ operations UC, which distribute phases across the basis states proportional to a cost function. We then show that when UC is combined with the standard Grover diffusion operator Us, one can achieve high probabilities of measurement for states corresponding to optimal and near optimal solutions while still only requiring O(π42N/M) iterations. In order to achieve these probabilities, a single scalar parameter ps is required, which we show can be found through a variational quantum–classical hybrid approach and can be used for heuristic solutions.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135458859","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}
引用次数: 1
Reality Does Not Shine, It Twinkles 现实不闪耀，它闪烁
Quantum Reports Pub Date : 2023-09-25 DOI: 10.3390/quantum5040040
William Sulis
{"title":"Reality Does Not Shine, It Twinkles","authors":"William Sulis","doi":"10.3390/quantum5040040","DOIUrl":"https://doi.org/10.3390/quantum5040040","url":null,"abstract":"Arguments have been made that the violation of the CHSH and similar inequalities shows that reality at the quantum level must be non-local. The derivation of Bell inequality is re-examined, and it is shown that violations of these inequalities merely demonstrate the existence of contextuality—they say nothing about the causal influences underlying such contextuality. It is argued that contextual systems do not possess enduring (propositional) properties, merely contingent properties. An example of a classical situation is presented: a two-player co-operative game, the random variables of which are consistently connected in the sense of Dzhafarov, which is contextual, and violates the CHSH inequality. In fact, it also violates the Tsirel’son bound. The key is that this system is generated, and its properties are disposed of, not determined.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135863469","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}
引用次数: 0
Research Trends in Quantum Computers by Focusing on Qubits as Their Building Blocks 以量子比特为基础的量子计算机研究趋势
Quantum Reports Pub Date : 2023-09-13 DOI: 10.3390/quantum5030039
Mohamad Taghi Dejpasand, Morteza Sasani Ghamsari
{"title":"Research Trends in Quantum Computers by Focusing on Qubits as Their Building Blocks","authors":"Mohamad Taghi Dejpasand, Morteza Sasani Ghamsari","doi":"10.3390/quantum5030039","DOIUrl":"https://doi.org/10.3390/quantum5030039","url":null,"abstract":"Quantum computing is a rapidly developing field that has the potential to revolutionize the way we process data. In this article, we will introduce quantum computers, their hardware and the challenges associated with their development. One of the key concepts in quantum computing is the qubit, which is the basic unit of quantum information. We will discuss this concept in greater detail, exploring how qubits work and the unique properties that make them so powerful. There are currently three leading models of quantum computers: superconducting, ion trap, and neutral-atom qubits. We will compare these models, highlighting their respective advantages and limitations, and discuss the current state of research in each area. In addition to exploring the hardware of quantum computers, we will also introduce some of the innovative research projects related to qubits. Finally, we will examine the market around the quantum computing industry, outlining some of the fundamental challenges we may face.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135741958","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}
引用次数: 1
Personal Identity and Uncertainty in the Everett Interpretation of Quantum Mechanics 埃弗雷特量子力学解释中的个人同一性和不确定性
Quantum Reports Pub Date : 2023-09-11 DOI: 10.3390/quantum5030038
Zhonghao Lu
{"title":"Personal Identity and Uncertainty in the Everett Interpretation of Quantum Mechanics","authors":"Zhonghao Lu","doi":"10.3390/quantum5030038","DOIUrl":"https://doi.org/10.3390/quantum5030038","url":null,"abstract":"The deterministic nature of EQM (the Everett Interpretation of Quantum Mechanics) seems to be inconsistent with the use of probability in EQM, giving rise to what is known as the “incoherence problem”. In this paper, I explore approaches to solve the incoherence problem of EQM via pre-measurement uncertainty. Previous discussions on the validity of pre-measurement uncertainty have leaned heavily on intricate aspects of the theory of semantics and reference, the embrace of either four-dimensionalism or three-dimensionalism of personhood, or the ontology of EQM. In this paper, I argue that, regardless of the adoption of three-dimensionalism or four-dimensionalism of personhood, the overlapping view or the divergence view of the ontology of EQM, the pre-measurement uncertainty approach to the incoherence problem of EQM can only achive success while contradicting fundamental principles of physicalism. I also use the divergence view of EQM as an example to illustrate my analyses.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135938097","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}
引用次数: 0
Optical Dromions for Spatiotemporal Fractional Nonlinear System in Quantum Mechanics 量子力学中时空分数阶非线性系统的光学子
Quantum Reports Pub Date : 2023-07-18 DOI: 10.3390/quantum5030036
Ihsan A. Khoso, Nek Muhammad Katbar, U. Akram
{"title":"Optical Dromions for Spatiotemporal Fractional Nonlinear System in Quantum Mechanics","authors":"Ihsan A. Khoso, Nek Muhammad Katbar, U. Akram","doi":"10.3390/quantum5030036","DOIUrl":"https://doi.org/10.3390/quantum5030036","url":null,"abstract":"In physics, mathematics, and other disciplines, new integrable equations have been found using the P-test. Novel insights and discoveries in several domains have resulted from this. Whether a solution is oscillatory, decaying, or expanding exponentially can be observed by using the AEM approach. In this work, we examined the integrability of the triple nonlinear fractional Schrödinger equation (TNFSE) via the Painlevé test (P-test) and a number of optical solitary wave solutions such as bright dromions (solitons), hyperbolic, singular, periodic, domain wall, doubly periodic, trigonometric, dark singular, plane-wave solution, combined optical solitons, rational solutions, etc., via the auxiliary equation mapping (AEM) technique. In mathematical physics and in engineering sciences, this equation plays a very important role. Moreover, the graphical representation (3D, 2D, and contour) of the obtained optical solitary-wave solutions will facilitate the understanding of the physical phenomenon of this system. The computational work and conclusions indicate that the suggested approaches are efficient and productive.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43488538","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}
引用次数: 0
Control Landscape of Measurement-Assisted Transition Probability for a Three-Level Quantum System with Dynamical Symmetry 具有动态对称性的三能级量子系统的测量辅助跃迁概率的控制景观
Quantum Reports Pub Date : 2023-07-13 DOI: 10.3390/quantum5030035
Maria Elovenkova, A. Pechen
{"title":"Control Landscape of Measurement-Assisted Transition Probability for a Three-Level Quantum System with Dynamical Symmetry","authors":"Maria Elovenkova, A. Pechen","doi":"10.3390/quantum5030035","DOIUrl":"https://doi.org/10.3390/quantum5030035","url":null,"abstract":"Quantum systems with dynamical symmetries have conserved quantities that are preserved under coherent control. Therefore, such systems cannot be completely controlled by means of only coherent control. In particular, for such systems, the maximum transition probability between some pairs of states over all coherent controls can be less than one. However, incoherent control can break this dynamical symmetry and increase the maximum attainable transition probability. The simplest example of such a situation occurs in a three-level quantum system with dynamical symmetry, for which the maximum probability of transition between the ground and intermediate states using only coherent control is 1/2, whereas it is about 0.687 using coherent control assisted by incoherent control implemented through the non-selective measurement of the ground state, as was previously analytically computed. In this work, we study and completely characterize all critical points of the kinematic quantum control landscape for this measurement-assisted transition probability, which is considered as a function of the kinematic control parameters (Euler angles). The measurement-driven control used in this work is different from both quantum feedback and Zeno-type control. We show that all critical points are global maxima, global minima, saddle points or second-order traps. For comparison, we study the transition probability between the ground and highest excited states, as well as the case when both these transition probabilities are assisted by incoherent control implemented through the measurement of the intermediate state.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44430749","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}
引用次数: 2
Quantum Probability from Temporal Structure 从时间结构看量子概率
Quantum Reports Pub Date : 2023-06-12 DOI: 10.3390/quantum5020033
M. Ridley
{"title":"Quantum Probability from Temporal Structure","authors":"M. Ridley","doi":"10.3390/quantum5020033","DOIUrl":"https://doi.org/10.3390/quantum5020033","url":null,"abstract":"The Born probability measure describes the statistics of measurements in which observers self-locate themselves in some region of reality. In ψ-ontic quantum theories, reality is directly represented by the wavefunction. We show that quantum probabilities may be identified using fractions of a universal multiple-time wavefunction containing both causal and retrocausal temporal parts. This wavefunction is defined in an appropriately generalized history space on the Keldysh time contour. Our deterministic formulation of quantum mechanics replaces the initial condition of standard Schrödinger dynamics, with a network of ‘fixed points’ defining quantum histories on the contour. The Born measure is derived by summing up the wavefunction along these histories. We then apply the same technique to the derivation of the statistics of measurements with pre- and postselection.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46371968","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}
引用次数: 0
Hydrogen-like Plasmas under Endohedral Cavity 自形腔下的类氢等离子体
Quantum Reports Pub Date : 2023-05-30 DOI: 10.3390/quantum5020030
S. Chowdhury, Neetik Mukherjee, Amlan K. Roy
{"title":"Hydrogen-like Plasmas under Endohedral Cavity","authors":"S. Chowdhury, Neetik Mukherjee, Amlan K. Roy","doi":"10.3390/quantum5020030","DOIUrl":"https://doi.org/10.3390/quantum5020030","url":null,"abstract":"Over the past few decades, confined quantum systems have emerged to be a subject of considerable importance in physical, chemical and biological sciences. Under such stressed conditions, they display many fascinating and notable physical and chemical properties. Here we address this situation by using two plasma models, namely a weakly coupled plasma environment mimicked by a Debye-Hückel potential (DHP) and an exponential cosine screened Coulomb potential (ECSCP). On the other hand, the endohedral confinement is achieved via a Woods-Saxon (WS) potential. The critical screening constant, dipole oscillator strength (OS) and polarizability are investigated for an arbitrary state. A Shannon entropy-based strategy has been invoked to study the phase transition here. An increase in Z leads to larger critical screening. Moreover, a detailed investigation reveals that there exists at least one bound state in such plasmas. Pilot calculations are conducted for some low-lying states (ℓ=1−5) using a generalized pseudo spectral scheme, providing optimal, non-uniform radial discretization.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41723122","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}
引用次数: 1
Anomalous Relaxation and Three-Level System: A Fractional Schrödinger Equation Approach 反常松弛与三能级系统：分数阶薛定谔方程方法
Quantum Reports Pub Date : 2023-05-26 DOI: 10.3390/quantum5020029
E. Lenzi, E. C. Gabrick, E. Sayari, A. S. M. de Castro, J. Trobia, Antonio M. Batista
{"title":"Anomalous Relaxation and Three-Level System: A Fractional Schrödinger Equation Approach","authors":"E. Lenzi, E. C. Gabrick, E. Sayari, A. S. M. de Castro, J. Trobia, Antonio M. Batista","doi":"10.3390/quantum5020029","DOIUrl":"https://doi.org/10.3390/quantum5020029","url":null,"abstract":"We investigate a three-level system in the context of the fractional Schrödinger equation by considering fractional differential operators in time and space, which promote anomalous relaxations and spreading of the wave packet. We first consider the three-level system omitting the kinetic term, i.e., taking into account only the transition among the levels, to analyze the effect of the fractional time derivative. Afterward, we incorporate a kinetic term and the fractional derivative in space to analyze simultaneous wave packet transition and spreading among the levels. For these cases, we obtain analytical and numerical solutions. Our results show a wide variety of behaviors connected to the fractional operators, such as the non-conservation of probability and the anomalous spread of the wave packet.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48672472","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}
引用次数: 1
The Open Systems View and the Everett Interpretation 开放系统观与埃弗雷特解释
Quantum Reports Pub Date : 2023-04-28 DOI: 10.3390/quantum5020027
Michael E. Cuffaro, S. Hartmann
{"title":"The Open Systems View and the Everett Interpretation","authors":"Michael E. Cuffaro, S. Hartmann","doi":"10.3390/quantum5020027","DOIUrl":"https://doi.org/10.3390/quantum5020027","url":null,"abstract":"It is argued that those who defend the Everett, or ‘many-worlds’, interpretation of quantum mechanics should embrace what we call the general quantum theory of open systems (GT) as the proper framework in which to conduct foundational and philosophical investigations in quantum physics. GT is a wider dynamical framework than its alternative, standard quantum theory (ST). This is true even though GT makes no modifications to the quantum formalism. GT rather takes a different view, what we call the open systems view, of the formalism; i.e., in GT, the dynamics of systems whose physical states are fundamentally represented by density operators are represented as fundamentally open as specified by an in general non-unitary dynamical map. This includes, in principle, the dynamics of the universe as a whole. We argue that the more general dynamics describable in GT can be physically motivated, that there is as much prima facie empirical support for GT as there is for ST, and that GT could be fully in the spirit of the Everett interpretation—that there might, in short, be little reason for an Everettian not to embrace the more general theoretical landscape that GT allows one to explore.","PeriodicalId":34124,"journal":{"name":"Quantum Reports","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46096524","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}
引用次数: 0
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