Quantum Scheme Research Articles

Fidelity and concurrence of entangled qudits between a trapped ion and two laser beams

A quantum scheme is presented by which a three-level trapped ion interacts with a two laser beams in the absence and presence of the e®ect of classical field. We analyze the impact of the classical ¯eld and the Lamb-Dicke parameter (LDP) on the dynamical behavior of entanglement quanti¯er, population probabilities and the geometric phase. Based on four different variations of these two effects, LDP = 0.1, LDP=0.01 and ¯ = 0.0, ¯ = 0.49, the time dependence of geometric phase and populations probabilities are shown. The ¯nding emphasizes that both the time-dependent and LDP play an important role in the development of the entanglement, the geometric phase, ¯delity, and populations probabilities. This in-sight may be very useful in various applications in quantum optics and information processing.

Authenticable Quantum Scheme for Secret Sharing Based on Local Distinguishability

Authenticable Quantum Scheme for Secret Sharing Based on Local Distinguishability

Non-Classical Rules in Quantum Games.

Over the last twenty years, quantum game theory has given us many ideas of how quantum games could be played. One of the most prominent ideas in the field is a model of quantum playing bimatrix games introduced by J. Eisert, M. Wilkens and M. Lewenstein. The scheme assumes that players’ strategies are unitary operations and the players act on the maximally entangled two-qubit state. The quantum nature of the scheme has been under discussion since the article by Eisert et al. came out. The aim of our paper was to identify some of non-classical features of the quantum scheme.

Properties of Pancharatnam Phase and Entanglement of a Five-Level Atom Interacting with a Squeezed Field

We introduce a quantum scheme where a single five-level atom interacts with a single-mode cavity field by a time-dependent coupling. During the interaction, the temporal behavior of the quantum entropy in the atomic basis is compared with that of the Mandel parameter used to quantify the nonclassical properties of the field. With the field prepared in a squeezed coherent state, the atomic quantum entropy is then used to quantify the entanglement or the nonlocal correlation of the five-level atom (5 LA) – field system. The influence of one- and two-photon transitions and the atomic motion on the degree of entanglement and the Pancharatnam phase is analyzed. The analysis emphasizes that both the time dependence and photon multiplicity play an important role in the evolution of the degree of entanglement, the Pancharatnam phase, and nonclassical properties. This insight may be very useful in various applications in quantum physics and quantum optics.

An Intrusion Resistant SCADA Framework Based on Quantum and Post-Quantum Scheme

The rapid emergence of quantum computing threatens current Supervisory Control and Data Acquisition (SCADA) security standards, mainly, American Gas Association (AGA)-12. Therefore, researchers are developing various security schemes based on either quantum or post-quantum algorithms. However, the efficiency of quantum algorithms impacts the security of the post-quantum digital signature scheme. We propose an intrusion resistant algorithm exploiting and applying quantum principles in the post-quantum signature algorithm. We use the Bennett 1992 (B92) protocol, a quantum key distribution scheme, to obtain the cipher, and the practical Stateless Hash-based Signatures (SPHINCS)-256 protocol to obtain a post-quantum signature. However, instead of Chacha-12, a well-known cryptographically secure pseudo-random number generator, we apply a quantum random number generator to obtain a truly random Hash to Obtain Random Subset (HORS) signature with Tree (HORST) secret key used in SPHINCS-256. We have implemented the design in Python with the Quantum Information Toolkit. We have validated the proposed algorithm using the Probabilistic Model Checking for Performance and Reliability Analysis (PRISM) and Scyther tools. Moreover, the National Institute of Standards and Technology (NIST) statistical tests show that the proposed algorithm key pairs have randomness of 98% and RSA and ECDSA are below 96%.

Quantum scheme of dissipative two qubits in a squeezed field: Entanglement and Fisher information

A clear relationship between the quantum version of Fisher information and the bipartite system entanglement has been explored recently. Known existing results for some quantum systems having strongly nonlocal correlations are still limited. In this paper, based on the interaction between a two-qubit and squeezed field, we investigate the correlation between the dynamical behavior of qubit-qubit entanglement and the quantum Fisher information (QFI). We focus on the effect of a number of photon multiplicity, low and high squeezing regime of the field on the dynamics of the QFI and entanglement quantifier. We show how the QFI and entanglement quantifier can be affected by the number of photon multiplicity and squeeze parameter during the time evolution of cases of absence and presence of dissipation effect. Our results exhibit the correlation between the entanglement quantifiers and the QFI with respect to the appearance of collapse and revival phenomena of the atomic inversion.

Quantum Algorithms for Solving Linear Regression Equation

Linear regression is one of the most important and common analytical methods in mathematical statistics. The letter studies a general model of linear regression problem based on least squares method, and investigates the impact of quantum algorithms on the time complexity of solving linear regression problem when quantum algorithms can be implemented on quantum computers. With the help of the general model of linear regression problem in terms of least squares method, we propose a novel simplified quantum scheme for solving linear regression equation based on the sparsity-independent quantum singular value estimation algorithm. For a linear regression equation with dimension n, our scheme can reduce the time complexity from O(Nn 2) to when both the condition number κ of related matrices and the reciprocal of precision ∈ are small in size O(play logN), where m is the dimension of the input u and N is the number of samples.

Quantum Version of a Generalized Monty Hall Game and Its Possible Applications to Quantum Secure Communications

AbstractIn this work, the authors propose a quantum version of a generalized Monty Hall game, that is, one in which the parameters of the game are left free and not fixed on its regular values. The developed quantum scheme is then used to study the expected payoff of the player, using both a separable and an entangled initial‐state. In the two cases, the classical mixed‐strategy payoff is recovered under certain conditions. Lastly, the authors extend the quantum scheme to include multiple independent players, and use this extension to sketch two possible application of the game mechanics to quantum networks, specifically, two validated, multi‐party, key‐distribution quantum protocols.

A Quantum Evolving Secret Sharing Scheme

An evolving secret sharing scheme is supposed to accommodate unbounded number (potentially infinite) of new participants over time and the dealer should not know the set of participants in advance. In this paper we initiate the study of quantum evolving schemes to share a quantum secret and show how to construct such a scheme where the qualified subsets (the sets which can reconstruct the secret) of participants are of increasing size as the number of participants increases with time. Share is given to new participants without modifying shares of old participants. While quantum secret sharing schemes which can accommodate new participants over time have been constructed before, a quantum scheme which can handle an unbounded and unspecified number of participants has not been considered so far. We also discuss the resilience of our scheme against a bounded number of quantum queries by an adversary/eavesdropper. This is achieved by using special functions for which lower bounds on their quantum query complexity is known.

Entanglement-Assisted Absorption Spectroscopy.

Spectroscopy is an important tool for probing the properties of materials, chemicals, and biological samples. We design a practical transmitter-receiver system that exploits entanglement to achieve a provable quantum advantage over all spectroscopic schemes based on classical sources. To probe the absorption spectra, modeled as a pattern of transmissivities among different frequency modes, we employ broadband signal-idler pairs in two-mode squeezed vacuum states. At the receiver side, we apply photodetection after optical parametric amplification. Finally, we perform a maximum likelihood decision test on the measurement results, achieving an error probability orders of magnitude lower than the optimum classical systems in various examples, including "wine tasting" and "drug testing" where real molecules are considered. In detecting the presence of an absorption line, our quantum scheme achieves the optimum performance allowed by quantum mechanics. The quantum advantage in our system is robust against noise and loss, which makes near-term experimental demonstration possible.

Optically induced diffraction gratings based on periodic modulation of linear and nonlinear effects for atom-light coupling quantum systems near plasmonic nanostructures

We investigate the quantum linear and nonlinear effects in a novel five-level quantum system placed near a plasmonic nanostructure. Such a quantum scheme contains a double-V-type subsystem interacting with a weak probe field. The double-V-subsystem is then coupled to an excited state by a strong coupling field, which can be a position-dependent standing-wave field. We start by analyzing the first-order linear as well as the third and fifth order nonlinear terms of the probe susceptibility by systematically solving the equations for the matter-fields. When the quantum system is near the plasmonic nanostructure, the coherent control of linear and nonlinear susceptibilities becomes inevitable, leading to vanishing absorption effects and enhancing the nonlinearities. We also show that when the coupling light involves a standing-wave pattern, the periodic modulation of linear and nonlinear spectra results in an efficient scheme for the electromagnetically induced grating (EIG). In particular, the diffraction efficiency is influenced by changing the distance between the quantum system and plasmonic nanostructure. The proposed scheme may find potential applications in future nanoscale photonic devices.

Loss tolerant quantum absorption measurement

The quantum statistics of entangled photon pairs promise greater performance for absorption measurements than can be achieved classically. However, the performance of a quantum approach is easily degraded under a loss of photons caused by experimental limitations. Here, we propose a loss-tolerant quantum scheme using quantum destructive interference in a nonlinear interferometer. Our theoretical results show that the loss-tolerant quantum scheme surpasses the conventional quantum scheme under photon loss at the detection stage. We demonstrate how photon losses at optical paths and mode-mismatches in a nonlinear interferometer affect the performance of our scheme. We also propose a hybrid approach to cope with the case where the quantum destructive interference is imperfect, and show that the hybrid scheme always surpasses the conventional quantum scheme.

Information Entropy Squeezing and Non-local Correlation Between a Two-Level Atom and Two-Mode Field Under the Classical Field Effect

This paper examines the squeezing on information entropy and entanglement on the basis of a quantum scheme contains two-mode interaction with time dependence of a two-level atom included external field. The proposed model is formulated by eliminating the external field after applying a certain transformation. The dynamics of information entropy squeezing and nonlocal correlation information for the system Hamiltonian are investigated. The influence of the classical field on the evolution of the squeezing and entanglement are estimated. Through the results will obtain the dynamic behavior of squeezing and entanglement is controlled using the external field.

Classical and quantum exact solutions for the anisotropic Bianchi type I in multi-scalar field cosmology with an exponential potential driven inflation

The anisotropic Bianchi type I in multi-scalar field cosmology is studied with a particular potential of the form V=V0e−[λ1ϕ1+⋯+λnϕn], which emerges as a condition between the time derivatives of their corresponding momenta. Using the Hamiltonian formalism for the inflation epoch with a quintessence framework we find the exact solutions for the Einstein-Klein-Gordon (EKG) system with different scenarios specified by the parameter λ2=∑i=1nλi2. For the quantum scheme of this model, the corresponding Wheeler-DeWitt (WDW) equation is solved by applying an appropriate change of variables and suitable ansatz.

Quantum algorithms of state estimators in classical control systems

In this paper, quantum algorithms are applied to the design of state estimators in classical control systems under the condition that quantum algorithms can be physically implemented. We demonstrate that the design of state estimators can be solved by quantum algorithms, which may achieve significant acceleration in comparison to traditional classical algorithms.The time complexity can be reduced from $O(n^6)$ to $O(qn)$ when the system matrix is sparse and the condition number $\\kappa$ and the reciprocal of precision $\\epsilon$ are small in size $O$(poly log$(n)$), where $n$ is the dimension of state $x(t)$ and $q$ is the dimension of input $u(t)$.Our research will provide an entire quantum scheme of constructing state estimators and can be regarded as an attempt to widen application scope of quantum computation.

Quantum image encryption algorithm based on generalized Arnold transform and Logistic map

In the era of big data, image security and real-time processing become more and more important and increasingly difficult to satisfy. To improve the security and processing efficiency of image encryption algorithm, an enhanced quantum scheme is proposed for generalized novel enhanced quantum image representation. The proposed quantum encryption scheme mainly consists of two-stage operation in order, i.e., twice scrambling based generalized Arnold transform and pixel encryption based on the quantum key image (which are generated and prepared based on Logistic map). In the first stage, generalized Arnold transform are employed to simultaneously disturb the coordinate information and pixel gray value of quantum plain image. Following that, the scrambled image is further encrypted into a quantum cipher image based on quantum key image, which is divided into three sub-processes in detail, i.e., CNOT operations, bit-plane scrambling and controlled perfect shuffle permutations are executed orderly. The quantum image decryption process can be easily implemented in a reverse way. The complete quantum circuit implementation for above two stages operation is constructed and analyzed in terms of quantum cost and time complexity. Compared to classical image processing algorithm, the investigated quantum encryption algorithm demonstrates an exponential speedup with computational cost of $${\rm O}\left( n \right)$$ for a $$2^{n} \times 2^{n}$$ quantum grayscale or color images. The proposed scheme is simulated and verified on a classical computer with MATLAB environments, i.e., not in a real quantum version that not considers the effects of quantum noise. Experimental results and numerical analysis indicate that the presented quantum algorithm has good visual effects and high security.

A Quantum secure sharing protocol for Cloud data based on proxy re-encryption

A quantum scheme for cloud data sharing based on proxy re-encryption is proposed. The user Alice stores the cipher-text of her data on cloud data center. When Alice wants to share her data with another user Bob, Alice is called the delegator and Bob is called the delegatee. The cloud service provider (called the proxy) can convert the delegator’s cipher-text into the delegatee’s cipher-text without decrypting the former, so that the delegatee can get the plain-text of Alice’s data with his private key. The proxy cannot obtain the plain-text of the user’s data stored on cloud data center. Delegator in the protocol should have the ability of producing Bell states, performing Bell basis and Z-basis measurements, and storing qubits. The quantum requirements for the delegatee are reduced. The delegatee needs to have the ability of reflecting and performing Z-basis measurement. One secret at a time (one-time one-pad) is theoretically implemented, especially when the same data is shared multiple times. The anti-selection plain-text attack security and the anti-selective cipher-text attack security are realized. Fine-granularity secret data sharing is achieved flexibly.

Quantum Analysis on Task Allocation and Quality Control for Crowdsourcing With Homogeneous Workers

Crowdsourcing has been emerging as a valid problem-solving model that harnesses a large group of contributors to solve a complicated task. However, existing crowdsourcing platforms or systems could suffer from task allocation and quality control problems. In this article, we first prove that there exist two dilemmas while tackling the above issues by using a game-theoretic approach. To overcome this challenge, we are focusing on exploiting quantum crowdsourcing schemes in which the welfare of requestor or worker can be maximized since quantum players share the extended strategy space, and the introduction of entanglement offers a new method of depicting fine-grained relations between players. Specifically, we propose a quantum game model for quota-oriented crowdsourcing game to address dilemmas in task allocation. The result indicates the dilemma based on classical strategy will disappear with the increment of entanglement degree. While in the quality-oriented crowdsourcing game, we adopt a density matrix approach to calculate the optimal payoffs of both sides, which demonstrates the superiority of our quantum strategy. Moreover, our quantum scheme is generic since it is compatible with the schemes from a classical perspective. Hence, our noteworthy quantum crowdsourcing schemes offer a promising alternative route for tackling dilemmas in crowdsourcing scenarios.

Resolution map in quantum computing: signal representation by periodic patterns

In this paper, a new concept of the resolution map is presented to extract periodic structures that compose the signal. The resolution map is described by using the frequency–time representation of the signal, which is known as the paired transform that provides the frequency-time representation of signals. The sequential calculation of resolution maps over the signal components of large sizes allows for calculating the small periodic structures, or patterns, which can be used for signal processing, for instance filtration, and from which the signal can be reconstructed. The length of the signal is considered to be a power of two, a case that fits well with qubit processing in quantum computing. The following new results are described: (1) the quantum scheme for the 1D discrete paired transform, (2) the quantum circuit for calculating the signal resolution map, (3) the quantum circuit for signal reconstruction from the resolution map, (4) different schemes for resolution maps for processing signals, and (5) the convolution of signals by their periodic patterns.

Quantum image sharpness estimation based on the Laplacian operator

In order to solve the high complexity of classical image processing, a quantum scheme for image sharpness estimation based on the Laplacian operator is proposed. The mean of grayscale gradients of all pixels is regarded as the sharpness estimation metric. A new quantum image representation model is presented by extending the Novel Enhanced Quantum Representation (NEQR) model, which is greatly useful for quantum image convolution. In quantum platforms, it has been shown that the mean calculation of numbers is rather difficult because the numbers are stored in a quantum superposition state. In order to solve this problem, we put forward an algorithm which essential idea is cyclically shifting the superposition state and iteratively calculating the mean of the new one and the original state. The mean can be obtained from the superposition state by only one quantum measurement. By analyzing the space complexity and time complexity, the scheme is far superior to classical ones in terms of resource consumption and execution speed. In addition, the results of simulation experiments show that for noiseless images, the performance of the scheme is consistent with subjective visual perception of images sharpness.