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The potential for quantum computers to perform some computational tasks significantly more quickly than traditional computers is exciting. where using trapped ions provided one of the most important theoretical and experimental benefits for building a quantum computer. This paper covers the theoretical research for some quantum gates which using in quantum information. The basic building blocks for computations and algorithms are logic gates. Quantum logic gates also the basic building blocks of quantum algorithms are implemented using trapped ions. The 40Ca+ trapped ions were employed in that study as an example of a quantum qubit in a Paul linear trap because they were contained in one dimension and could be easily handled and manipulated in the quantum state. We used the simulation system in the MATLAB program to present the logic gates that using in Quantum circuits, and illustrate the processes of rotation and manipulation of the quantum state by represented it on a Bloch sphere. [ABSTRACT FROM AUTHOR]

Urbanization plays an important role in the field of environmental science and for the growth of green society. Urbanization scaled up with the economical benefits in developing countries and in countries making sustainable development process on ecological paths with higher efficiency on the growth of the ecosystem. In civilization due to urbanization there are problems such as air excellence corrosion, limitations on the space for survival, issues in the health of urban. Towards the perspective advancement of urban ecology it is distorted from a speculative study in the field of interdisciplinary. This article provides a new idea using Machine Learning and Quantum Computing to produce an output where it gives an efficient building idea of integrating plants and trees with or around the building. The dataset are emission and absorption of carbon dioxide. In order to create the X_features, we either use approximation factors or real-time remote sensing. The main goal of the system is to train them with different machine learning models and show that if the data set time complexity increases exponentially, Quantum Computers can be used to run the models. [ABSTRACT FROM AUTHOR]

Quantum computing technology is in an evolutionary stage with the active involvement of more than 600 renowned companies and almost 30 national laboratories and government agencies worldwide as per the report published by The Quantum Insider. The efficacy of any emerging technology is assessed through three factors: time, cost, and quality. Parallel computing is possible in quantum computers due to superposition and entanglement of qubits which offers exceptional speed advantage in cracking complex problems. Thus the two requirements of time and cost are fulfilled. However, the quality aspect is lagging on account of a few constraints. This technology is poised to become a disruptive technology as a lot of research and development activities are being carried out globally to improve the quality and accuracy of the results to acceptable standards. In the next decade, this exotic technology will transform the entire industry and turbocharge innovation globally. [ABSTRACT FROM AUTHOR]

Based on an idea by Richard Feynman, quantum computing is a relatively new technological innovation that promises to very quickly solve problems that one usually encounters in Science and Engineering (i.e., optimization and numerical problems). Currently, there are no full-blown quantum computers; nevertheless, researchers are working on quantum technology, if one is allowed. to say so, propose new ideas, solve old technological problems, implement new hardware design principles, etc., and all these Developments are quite encouraging for the future of quantum computing. Given these facts, it makes sense to propose the use of quantum technology for the solution of common and not-so-common problems encountered in Science and Technology today. [ABSTRACT FROM AUTHOR]

The paper presents a study of the process of stabilization of zinc silicate nanoparticles with amino acids. Quantum-chemical modeling of the process of interaction of zinc silicate with amino acids was carried out in the QChem software using the molecular editor – IQmol. As a result of the quantum-chemical modeling, it was found that all compounds of zinc silicate with amino acids are energetically favorable (ΔE > 2358 kcal/mol), and have a high index of chemical rigidity in the range from 0.092 to 0.157 eV, which indicates the high stability of the presented compounds. The interaction of zinc silicate with lysine has the highest index of chemical rigidity. The most energetically favorable is the ZnSiO3 – Val interaction (ΔE = 2359.913 kcal/mol). The samples were also studied by IR spectroscopy on an FSM-1201 instrument. As a result of the analysis of the obtained data, it was found that the interaction of the amino acid with the zinc silicate surface proceeds through the formation of a Si-O-N chemical bond between ZnSiO3 and the amino group of the amino acid. The obtained data confirm the results of computer-quantum-chemical modeling. [ABSTRACT FROM AUTHOR]

Machine learning is the process of discovering patterns in data and using those patterns to forecast or predict future occurrences of those patterns. The machine learning process consists of three steps: input data management, model construction, and model evaluation. Combining machine learning and quantum computing allows for the design and operation of quantum circuits with behavior resembling that of classical machine learning. Variable quantum circuits are frequently used in quantum machine learning. Parameterized variables, a crucial part of variable quantum circuits, must be adjusted in order to achieve good performance of these circuits. It is possible to modify parameterized variables in a variety of ways, such as by using gradient methods or linear programming to determine the circuit's optimal point. This study proposes a method for automatically designing a variational quantum circuit to classify the different datasets, including the well-known 1-dimensional and 2-dimensional datasets, iris and MNIST, using a genetic algorithm to find the best values for the parameterized variables. The Qiskit quantum simulation tools are employed in these experiments. The results show that genetic algorithms can find solutions with greater accuracy than linear-based optimizers by 94 percent and 37.5 percent, respectively, for the iris dataset and the MNIST dataset. [ABSTRACT FROM AUTHOR]

Quantum machine learning is a new field of study that aims to apply the advantages of quantum computing, such as superposition, which is one of the intriguing properties that could speed up computation, to machine learning. Like classical machine learning models, quantum machine learning models can learn from specific input data and perform specific prediction tasks. However, quantum machine learning models are currently in the form of quantum circuits with parameterizable gates. In this paper, the implementation of a quantum classification model is investigated using the two most well-known quantum machine learning development tools: Cirq with TensorFlow Quantum (TFQ) and Qiskit with PyTorch. The quantum classification circuit is trained to recognize images of handwritten digits using the MNIST dataset. However, because the quantum computer is still in development and is difficult to access and use, quantum simulators are the best alternative for the time being. The performance of the quantum classification model implemented by the two development tools is then compared in this paper experimentally using quantum simulators on two different hardware configurations. In addition, the experimental setups differ in the number of input qubits used to store the image's classical pixel values. Finally, the wall time and CPU time used to run the training process, as well as classification accuracy, are examined. In terms of accuracy, Qiskit with PyTorch outperforms Cirq with TFQ only in the lower number of qubits but the results are similar in the higher number of qubits. The experiment results in terms of run-time are highly different. From the result, we find that Cirq is noticeably faster than Qiskit in every experiment by at least 90 times. [ABSTRACT FROM AUTHOR]

We propose a high-performance state-vector emulator of a gate-based quantum processors developed in the Rust programming language. It supports OpenQASM 2.0 programming language [1] for quantum circuits specification and has a user-friendly Python based API. We present a wide range of numerical benchmarks of the emulator. We expect that our emulator will be used for design and validation of new quantum algorithms. [ABSTRACT FROM AUTHOR]

This study aimed to design a media for physics learning based on Android apps. The learning media are designed based on conceptual discussion, simulation, and video with mini-quizzes containing cognitive, affective, and psychomotor aspects. Android apps have been tested to be valid, practical, and effective for use in the classroom. The adopted model development is the ADDIE model which stand for Analysis, Design, Development, Implementation and Evaluation. The media were tested by physics education expert and experimented on a small group tests. Data were collected through questionnaires analyzed through descriptive statistics, interviews, and observations, and analyzed through qualitative analysis. The physics learning media was produced named Phy-Cast (Physics-Cast). The Android apps contain several senior high school physics topics namely discussing parabolic motion, fluid statics, and quantum phenomena. As a result of the study, it was found that Phy-Cast, physics learning media, has good compatibility, and there is no major problem when used. Phy-Cast has been tested in a small group, and the results have shown that the learning tool is valid, practical, and effective for use in the learning process. [ABSTRACT FROM AUTHOR]

Quantum computers are here, and the search for applications and use of these allow us to overcome the limits that today's hardware information processing gives us is constantly going on. Quantum machine learning is one of the many emerging fields that use quantum computers to process information. In this paper, we present a method and a set of experiments where we see the potential and capacity of the Noisy intermediate-scale quantum hardware for the execution of different models having as the basis in some of them the quantum algorithm corresponding to the Quantum Fourier Transform. With this, we demonstrate the effectiveness of how this algorithm can enhance the performance of quantum computations in quantum machine learning models in near-term applications. We used the systems offered by IBM Quantum and the cross-platform Python library for quantum differentiable programming Pennylane by Xanadu Quantum Technologies Inc. [ABSTRACT FROM AUTHOR]

We study the implementation of Grover's algorithm in an Ising spin chain quantum computer. In our scheme, we removed the application of time delay whenever a qubit operation is performed. Instead, we introduced a set of modified pulses that utilizes the interaction of the neighboring qubit. In principle, the absence of time delay pulses allows the overall rotation pulses to be applied simultaneously to execute a gate. We show that the fidelity remains high after continuous application of π/2 pulses. The error arising from the unitary evolution is minimized by using soft pulses. Finally, the probability of finding the target state remain bounded through the application of fixed-point quantum search scheme. [ABSTRACT FROM AUTHOR]

The rapid development of quantum computing and cryptography unleash the thinking of an internet network that is based on quantum mechanics. The quantum-based internet is predicted to be more secure than the classical one due to its entanglement distribution strategy. The main challenge that can face the quantum internet is the nature of quantum bits which require special circumstances to stay stable. Quantum bit entanglement is fragile and decoherence which leads to missing the entangled photons and disconnection of communication. Recently, different solutions have been suggested to overcome this challenge which are mainly counting on the technologies and materials that can increase the photon lifetime and enhance the ability to transfer it over long distances without losses. In this paper a general overview of this new and interesting research topic is presented which can be considered as an onset for the researchers who are interested in this promising field. [ABSTRACT FROM AUTHOR]

In this busy world, there is an estimation of 3.5 exabytes of information data been generated in a single day and the data is shared on more than 10 million computing devices. As We, human beings are wholeheartedly dependent on the digital based computing devices for knowledge sharing by means of text and image information for each and every commotion of the day. Now, the sustenance of life without computing is considered as perplexed. As per a report submitted by association of semiconductor industries which states that by 2040, it is not possible to provide power to computer machine which is available in good running conditions present throughout the globe. It's a known fact that the fundamental functionality of a computer system to modify and save the information data. Presently all the computer systems are using the classical technique to manipulate the data using single bits that stores the information data in form of 0's and 1's. [1To overcome the inability stated by semiconductor industry, the quantum physics has come up with a new concept which specifies that the quantum elements have the tendency to move in both directions i.e. fore and rear directions and its presence can be felt in both places at same time and travel itself instantly]1. This peculiar tendency of quantum particles had lead to quantum computing. The most critical property of quantum computing is its enhanced asset for characterization and construction of information data. A mechanism is developed to work on various operations for computation of information data. Qubits i.e quantum bits are used in Quantum computing, it consist of a third state excluding the traditional data states 0 and 1.Hence the time duration taken by quantum computing to modify the information data is much lesser than that of traditional computing. In this paper, we try to explore the concepts of quantum computing, how it is related to physics, how it can be used and implemented. [ABSTRACT FROM AUTHOR]

In this digital era, the amount of sensitive data getting transferred every day is very high, the digitization of all data brought a lot of advantages along with serious security threats. The security standards exist in present scenario provides three basic services such as Confidentiality, Integrity, and Authentication (CIA), the two common types of symmetric and asymmetric algorithms are being used at different levels and capacities. The emerging of new technologies and high computing facilities makes the existing standards vulnerable to different attacks and security threats. There is a need of developing a new set of cryptographic algorithms those are quantum-safe, which means, the arrival of quantum computers can break any sized keywithin a polynomial solvable time, the quantum computers can do prime factorization in realistic time complexities. There are new and smart cryptanalysis emerging to break the existing standards such as Advanced Encryption Standard (AES) and RSA, these algorithms are ruling the cyber world for more than two decades. In this research paper, a new concept of using polynomials to encrypt and decrypt data is proposed, however, the power of polynomials are not fully explored in cryptography, we use Newton Raphson method and its advancements to implement a new cryptography algorithm that is more accurate and faster than existing standards. The proposed algorithm doesn't use any fixed size to avoid cryptanalysis and attacks based on key sizes, the highly intensive computing can break any length of key in realistic time delays, so variable sized key solves this problem in our approach. [ABSTRACT FROM AUTHOR]

Ettore Majorana, in his short life, unintendedly has uncovered the most profound problem in quantum computation by his discovery of Majorana fermion, a particle which is its own anti-particle. Owing to its non-Abelian exchange statistics, Majorana fermions may act as a qubit for a universal quantum computer which is fault-tolerant. The existence of such particle is predicted in mid-gap states (zero modes) of a topological superconductor as bound states that have a highly entangled degenerate ground state. This introductory overview will focus on the simplest theoretical proposals of Majorana fermions for topological quantum computing in superconducting systems, emphasizing the quest from the scalability problem of quantum computer to its possible solution with topological quantum computer employing non-Abelian anyons on various platforms of certain Majorana fermion 'signature' encountered. [ABSTRACT FROM AUTHOR]

The Second Law of thermodynamics states that the entropy of the isolated system is non-diminishing in the course of time evolution. In quantum systems, the Second Law can be violated by adding to the system the quantum Maxwell's demon (QMD) which reduces entropy without energy exchange. However, extending the system by including into it the QMD itself, restores the Second Law. Remarkably, enlarging system with one more demon we return to the initial situation. Therefore by sequential adding the QMD, we can construct the energy-conserving macroscopic system which evolves in time with decreasing the entropy. Here we demonstrate this general principle on the IBM quantum computer how extending the system by one extra qubit, we still observe the entropy decreasing, thus violating the second law. We utilize five QMD implemented by the extra qubits since decoherence effects restrict the number of possible qubit additions. [ABSTRACT FROM AUTHOR]

To simulate a quantum system with continuous degrees of freedom on a quantum computer based on quantum digits, it is necessary to reduce continuous observables (primarily coordinates and momenta) to discrete observables. We consider this problem based on expanding quantum observables in series in powers of two and three analogous to the binary and ternary representations of real numbers. The coefficients of the series ("digits") a re, t herefore, Hermitian o perators. We investigate the corresponding quantum mechanical operators and the relations between them and show that the binary and ternary expansions of quantum observables automatically lead to renormalization of some divergent integrals and series (giving them finite values). [ABSTRACT FROM AUTHOR]

We use the Variational Quantum Eigensolver (VQE) as implemented in the Qiskit software package to compute the ground state energy of small molecules derived from water, H2O, and hydrogen cyanide, HCN. The work aims to benchmark algorithms for calculating the electronic structure and energy surfaces of molecules of relevance to prebiotic chemistry, beginning with water and hydrogen cyanide, and to run them on the available simulated and physical quantum hardware. The numerical calculations of the algorithms for small quantum processors allow us to design more efficient protocols to be run in real hardware, as well as to analyze their performance. Future implementations on accessible quantum processing prototypes will benchmark quantum computers and provide tests of quantum advantage with heuristic quantum algorithms. [ABSTRACT FROM AUTHOR]

Cryptography is a branch of mathematics used in digital security systems. Some cryptographic algorithms, such as RSA, depending on the prime factorization of integers. However, quantum computers might be a threat to some algorithms in cryptography. One of the mathematicians' efforts in finding alternatives to create new security technologies in cryptography is to study the abstraction of prime numbers. The prime submodule is one of the prime numbers abstraction, which was introduced by Dauns in 1978. Lately, the prime submodules were generalized into weakly prime submodules and almost prime submodules. This study will examine the characteristics of prime, weakly prime, and almost prime of cyclic submodules on ℤ−module ℤn[i]. The results are if n is a prime number, then the cyclic submodule is prime submodule on ℤ−module ℤn[i] and the cyclic almost prime submodule equivalent with cyclic weakly prime submodule on ℤ−module ℤn[i]. [ABSTRACT FROM AUTHOR]

The fundamental link between physics and computation leads to an exciting field of quantum computation. Since the birth of the programmable digital computer, random number generators in computers have been developed. In principle, the pseudo random number generators currently implemented in digital computers are predictable. However, a quantum random number generator is employed to ideally generate unpredictable random numbers. In this essay, we explain why a one-qubit quantum computer can be a quantum random number generator and how this leads to justifying the foundations of quantum mechanics. [ABSTRACT FROM AUTHOR]

The work discusses validation of properties of quantum circuits with many qubits using non-universal set of quantum gates ensuring possibility of effective simulation on classical computer. An understanding analogy between different models of quantum chains is suggested for clarification. An example with IBM Q Experience cloud platform and Qiskit framework is discussed finally. [ABSTRACT FROM AUTHOR]

Linear optics is a promising physical architecture for the implementation of the quantum computing devices. The key element of the linear optical quantum computer is an optical circuit realizing the sequence of transformations defined by the required quantum algorithm. The most prominent approach is the reconfigurable integrated photonics which allows to miniaturize standard optical setups on the chosen integrated photonic platform. In this paper, we propose a universal linear-optical circuit design comprised of the series of multiport beamsplitters followed by the phaseshifting elements. The proposed unitary composer device can be straightforwardly implemented using standard integrated photonic technologies. We provide guidelines for appropriate multiport beamsplitter fabrication using integrated waveguide lattices. To exemplify the performance of the composer we provide the six-mode CNOT linear optical gate circuit design fitted to described interferometric circuit. [ABSTRACT FROM AUTHOR]

Many commonly used public-key cryptosystems will become insecure once a scalable quantum computer is built. New cryptographic schemes that can guarantee protection against attacks with quantum computers, so-called post-quantum algorithms, have emerged in recent decades. One of the most promising candidates for a post-quantum signature scheme is SPHINCS+, which is based on cryptographic hash functions. In this contribution, we analyze the use of the new Russian standardized hash function, known as Streebog, for the implementation of the SPHINCS+ signature scheme. We provide a performance comparison with SHA-256-based instantiation and give benchmarks for various sets of parameters. [ABSTRACT FROM AUTHOR]

Methods of processing quantum data become more important as quantum computing devices improve their quality towards fault tolerant universal quantum computers. These methods include discrimination and filtering of quantum states given as an input to the device that may find numerous applications in quantum information technologies. In the present paper, we address a scheme of a classification of input states, which is nondestructive and deterministic for certain inputs, while probabilistic, in general case. This can be achieved by incorporating phase estimation algorithm into the hybrid quantum-classical computation scheme, where quantum block is trained classically. We perform proof-of-principle implementation of this idea using superconducting quantum processor of IBM Quantum Experience. Another aspect we are interested in is a mitigation of errors occurring due to the quantum device imperfections. We apply a series of heuristic tricks at the stage of classical postprocessing in order to improve raw experimental data and to recognize patterns in them. These ideas may find applications in other realization of hybrid quantum-classical computations with noisy quantum machines. [ABSTRACT FROM AUTHOR]

Superconductors are demonstrated to profoundly differ in arrangement yet elusive and mysterious. To understand the Josephson Effect, it is advisable to first acquire some notion about the origin of the superconductivity. Macroscopically, superconductivity manifests itself as a lack of resistance, so that the current flows with no obstacles. The practical applications of superconductivity are consistently improving each year. However, the real utilization of superconducting devices is constrained by the way that they should be cooled to low temperatures to move toward becoming superconducting. The revelation of high-Tc superconductors broadens the feasible application of superconductors. The Josephson Effect has enabled the advancement of unique electrical devices and systems including SQUIDs, quantum computers, analog to digital (A/D) converters, Josephson voltage standard, THz emitters and detectors, single flux quantum devices, etc. In this research paper, we studied the Superconducting materials, its characteristics and applications in physics. [ABSTRACT FROM AUTHOR]

This paper shows a novel way of simulating a Markov process by a quantum computer. The main purpose of the paper is to show a particular application of quantum computing in the field of stochastic processes analysis. Using a Quantum computer, the process could be superposed, where the random variables of the Markov chain are represented by entangled qubit states, which gives the great opportunity of having all the possible scenarios simultaneously. [ABSTRACT FROM AUTHOR]

The qubit state is represented by a coherent superposition of its orthonormal basis states (|0❭ and |1❭). The probability distribution of a qubit is a discrete probability distribution of the qubits probability amplitudes. Setting a custom probability amplitudes allows a qubit to evolve to any desired state. In this paper a controlled n-root of X gate is simulated on a real quantum processor using IBMs Quantum Experience platform. A custom quantum gate could be constructed where the only inputs are the control and target qubits and the desired probability distribution for the target qubit. [ABSTRACT FROM AUTHOR]

Computer simulation of the interaction of diatomic A2 molecules (A = C, Si, N, P, O, S) with a super-small single-walled carbon nanotube (SWCNT) sensor was performed. The nonlocal density functional B3LYP / 3-21G (ORCA package) was used to study the supratomical nanosystem. For all molecules, it has been shown that the most preferable orientation of their axis is perpendicular to the outer surface of the SWCNT. Significant differences were found in the adsorption of molecules of group IV a (C, Si), group V a (N, P) and group VI a (O, S) of the periodic table of elements. The calculation showed that the chemisorption of the molecules C2 and Si is characterized by binding energies of 2.91 eV, 1.51 eV and equilibrium distances from the SWCNT surface of 1.39 A and 2.91 A, respectively. For a C2 molecule, a covalent bond with a pair of carbon atoms is preferred, while for a Si2 molecule, a covalent bond with one of the carbon atoms is more stable. In turn, for the N2, P2, O2, S2 molecules, it is preferable to be located in the center of carbon sextet at a distance from the surface of the SWCNT: 3.00 A, 3.17 A, 2.66 A, 2.96 A with binding energy: 0.15 eV, 0.27 eV, 0.39 eV, 0.52 eV, respectively. [ABSTRACT FROM AUTHOR]

The paper presented is a solution of a numerical simulation of the linear wave in a 2-D numerical wave tank (NWT) to understand the characteristic behavior of the ocean wave in the intermediate depth of water (0.05:≤d/L:≤0.5) by FLUENT software and using the volume of fluid (VOF) method. Linear waves of amplitude a = 0.2m are generated in an NWT of length lx = 50m and height lz = 10m by a flap-type wave maker. In this study, different parameters such as depth of water d = 5m, wave height H = 0.4m, wavelength L = 13.793m and 22.212m and the time period T = 3s and 4s, wave steepness H/L = 0.0294 and 0.0180 and relative depth d/L =0.3682 and 0.2251 are considered for analysing the behavior of the ocean wave. The entire analysis is carried out at a distance x = 10m from the wave maker at the free surface of the water and also just 1m below from the free surface. It shows that the numerical results of waves are in good agreement with the theoretical results. It is observed from the simulation that the horizontal and vertical velocities (u&w) are more at the free surface for the time period T = 3s compared to the time period T = 4s and the velocities are gradual decreases towards the bottom of the tank. It is also observed that the dynamic pressure at the free surface (d = 0) is less as compared to the bottom (d = 5m). [ABSTRACT FROM AUTHOR]

Research in the Internet of Things (IoT) is increasing the studies in security and privacy aspects. IoT applications is expected to have difficulties in security and privacy issues in the near future. Speed improvement of quantum computers threatens the crypto algorithms used. Strong Mathematics encryption algorithms in today's World can cause weaknesses later. They can be solved by the computers which have large enough transaction volume in the labs. Changes in technology require the change in approaches to security solutions. Smart objects can be managed over the network, including critical applications. The basis of security on data lies in the science of cryptography. Privacy and fidelity of data collected over IoT and its accurate transmission are very important. This study provides an approach on reliability of next-generation encryption algorithm in the context of objects' relativity. [ABSTRACT FROM AUTHOR]

The application of quantum mechanics contributes to the field of cryptography with very important advantage as it offers a mechanism for detecting the eavesdropper. The pioneering work of quantum key distribution uses mutually unbiased bases (MUBs) to prepare and measure qubits (or qudits). Weak mutually unbiased bases (WMUBs) have weaker properties than MUBs properties, however, unlike MUBs, a complete set of WMUBs can be constructed for systems with composite dimensions. In this paper, we study the use of weak mutually unbiased bases (WMUBs) in quantum key distribution for composite dimensional finite systems. We prove that the security analysis of using a complete set of WMUBs to prepare and measure the quantum states in the generalized BB84 protocol, gives better results than using the maximum number of MUBs that can be constructed, when they are analyzed against the intercept and resend attack. [ABSTRACT FROM AUTHOR]

We review the recent progress of quantum annealing. Quantum annealing was proposed as a method to solve generic optimization problems. Recently a Canadian company has drawn a great deal of attention, as it has commercialized a quantum computer based on quantum annealing. Although the performance of quantum annealing is not sufficiently understood, it is likely that quantum annealing will be a practical method both on a conventional computer and on a quantum computer. [ABSTRACT FROM AUTHOR]

Deterministic doping by single ion implantation, the precise placement of individual dopant atoms into devices, is a path for the realization of quantum computer test structures where quantum bits (qubits) are based on electron and nuclear spins of donors or color centers. We present a donor - quantum dot type qubit architecture and discuss the use of medium and highly charged ions extracted from an Electron Beam Ion Trap/Source (EBIT/S) for deterministic doping. EBIT/S are attractive for the formation of qubit test structures due to the relatively low emittance of ion beams from an EBIT/S and due to the potential energy associated with the ions' charge state, which can aid single ion impact detection. Following ion implantation, dopant specific diffusion mechanisms during device processing affect the placement accuracy and coherence properties of donor spin qubits. For bismuth, range straggling is minimal but its relatively low solubility in silicon limits thermal budgets for the formation of qubit test structures. [ABSTRACT FROM AUTHOR]

Here, I summarize the results presented in B.Kraus, Phys. Rev. Lett. 107, 250503 (2011). Recently, it has been shown that certain circuits, the so-called match gate circuits, can be compressed to an exponentially smaller universal quantum computation. We use this result to demonstrate that the simulation of a 1-D Ising chain consisting of n qubits can be performed on a universal quantum computer running on only log(n) qubits. We show how the adiabatic evolution can be simulated on this exponentially smaller system and how the magnetization can be measured. Since the Ising model displays a quantum phase transition, this result implies that a quantum phase transition of a very large system can be observed with current technology. [ABSTRACT FROM AUTHOR]

Quantum computers have the potentials to solve certain problems faster than classical computers. In quantum computer, entanglement is one of the elements beside superposition. Recently, with the advent of quantum information theory, entanglement has become an important resource for Quantum Information and Computation. The purpose of this paper is to discuss the separability criteria and method of measurement for entanglement. This paper is aimed at viewing the method that has been proposed in previous works in bipartite and multipartite entanglement. The outcome of this paper is to classify the different method that used to measure entanglement for bipartite and multipartite cases including the advantage and disadvantage of each method. [ABSTRACT FROM AUTHOR]

Solving the quantum-mechanical many-body problem requires scalable computational approaches, which are rooted in a good understanding of the physics of correlated electronic systems. Interacting electrons in a magnetic field display a huge variety of eigenstates with different internal structures, which have been probed experimentally in the Hall effect. The advent of highperforming graphics processing units has lead to a boost in computational speed in particular for classical systems. In the absence of a quantum-computer, it is thus of importance to see how quantum-mechanical problems can be cast into a seemingly classical dynamics, which can be efficiently implemented. At the same time, such mappings provide insights into the quantum-toclassical transition of many-body systems. [ABSTRACT FROM AUTHOR]

In quantum information, the qubit is not represented by a full spinor in space and in time as the z spinor below: Ψ0(z) = (2πσ20)-12e-z24σ20(cosθ02e-iϕ02sinθ02eiϕ02) but by a simplified spinor without spatial extension Ψ = (cosθ02e-iϕ02sinθ02eiϕ02) This simplification is the basis of our first criticism of the quantum computer concept. Indeed, the demonstrations explaining the interest of the Deutsch, Glover and Shor algorithms are based on calculations using the factorization of entangled qubits. These factorizations are accurate for spinors without spatial extensions, but only approximate for real spinors with spatial extensions. Through the spatial extension question, we also revisit the Stern and Gerlach experiment, to explain the decoherence, the individual impacts and the quantization. We conclude in two other criticism what this spin interpretation implies for the feasibility of quantum computers. A second, more fundamental criticism concerns the existence of the (single) spin-based qubit itself. Indeed, we show that the variables of space and spin are not factorizable duringmeasurement. It seems that the qubit, which is a simplified spinor, does not exist as individual object, at least during the measurement. A third criticism deals with the completness of quantum mechanics. Our analysis explains very simply the negative results of the NMR technique, developed by Chuang et al, which does not use quantum objects individually. The spinor spatial extension takes into account the initial position z0 of the particle. [ABSTRACT FROM AUTHOR]

Can we reduce Quantum Field Theory (QFT) to a quantum computation? Can physics be simulated by a quantum computer? Do we believe that a quantum field is ultimately made of a numerable set of quantum systems that are unitarily interacting? A positive answer to these questions corresponds to substituting QFT with a theory of quantum cellular automata (QCA), and the present work is examining this hypothesis. These investigations are part of a large research program on a quantum-digitalization of physics, with Quantum Theory as a special theory of information, and Physics as emergent from the same quantum-information processing. A QCA-based QFT has tremendous potential advantages compared to QFT, being quantum ab-initio and free from the problems plaguing QFT due to the continuum hypothesis. Here I will show how dynamics emerges from the quantum processing, how the QCA can reproduce the Dirac-field phenomenology at large scales, and the kind of departures from QFT that that should be expected at a Planckscale discreteness. I will introduce the notions of linear field quantum automaton and local-matrix quantum automaton, in terms of which I will provide the solution to the Feynman's problem about the possibility of simulating a Fermi field with a quantum computer. [ABSTRACT FROM AUTHOR]

We present an experimental demonstration of quantum smoothing, a non causal version of quantum parameter estimation that has applications from gravitational wave detection to quantum key distribution. An existing technique for this type of parameter estimation is quantum filtering, which uses past observations only. The technique presented here is time-symmetric that uses past and future observations to obtain a more precise estimate. We couple this innovative estimation technique with an adaptive detection scheme to demonstrate an estimation of the optical phase of light measured to be 2.24 ± 0.14 times better than the standard quantum limit. This approaches our theoretically derived prediction of a mean square error improvement of [formula] times over the standard quantum limit [1]. [ABSTRACT FROM AUTHOR]

Optical implementations of qubits play an important role for quantum information science. Photons are ideal carriers of quantum information due to low decoherence rates and are easily controllable by standard off-the-shelf components. Over the last decade the degree of control over photonic single- and two-qubit operations has improved substantially, which recently enables the complex state engineering of various multi-photon states. The control of current four- and six-photon entangled states provides access for the investigation of interesting properties of multi-particle entangled states and for overcoming the random nature of spontaneous emission sources. [ABSTRACT FROM AUTHOR]

Spin is a quantum property of electrons. For spin-based quantum information technology, preparation and read-out of the electron spin state should be spin coherent. We demonstrate that the polarization coherence of light can be transferred to the spin coherence of electrons in a semiconductor quantum nanostructure, and the prepared coherence of the electron spin can also be read out with light by the developed tomographic Kerr rotation method. We also demonstrate that a single photon is efficiently converted (∼27%) into a single electron trapped in a gate-defined quantum dot, where the g-factor of electrons is tuned to zero, and the charge state is detected with an adjacent quantum point contact without destructing the spin state. We further demonstrate that the spin coherence of a single electron trapped in one of double quantum dots is electrically manipulated with a microwave applied to the gate and read out via the Pauli spin blockade phenomenon. All of these functions are needed to build all semiconductor quantum repeaters and distributed quantum computers. [ABSTRACT FROM AUTHOR]

A promising proposal by B. Kane for a scalable silicon quantum computer requires the placement of 31P atoms 20 nm apart and 10 nm below the surface in pure 28Si to 1 nm precision. This paper presents progress on a scheme for laser cooling and trapping single 31Si atoms in a magneto-optical trap (MOT), resonantly ionizing that one atom near threshold, and softly depositing the single 31Si+ ion in Si to nm precision at ∼100 eV. A few hours after deposition, 31Si beta decays to 31P+. The hyperfine structure and isotope shifts of the 221.7 nm cooling transition for the stable isotopes of Si have been measured with precision for the first time. Sufficient power for the MOT at this wavelength has also been demonstrated. New autoionizing states near threshold have been found and ionization cross sections determined. The velocity distributions of laser ablated Si atoms have been measured, and unexpected results have been found. Construction of the MOT and design of the ion optics are underway. [ABSTRACT FROM AUTHOR]

We apply quantum control techniques to a long spin chain by acting only on two qubits at one of its ends, thereby implementing universal quantum computation by a combination of quantum gates on these qubits and indirect SWAP operations across the chain. It is shown that the control sequences can be computed and implemented efficiently. We discuss the application of these ideas to physical systems such as superconducting qubits in which full control of long chains is challenging. [ABSTRACT FROM AUTHOR]

We describe a scalable architecture for general-purpose quantum computation based on trapped ions and photonic interconnect network. The quantum computer is made up of several elementary logic units (ELUs) each containing a modest number of trapped ions representing physical qubits. Each ELU is provided with an optical communication port through which a photon entangled with a communication ion is extracted. Quantum entanglement is distributed between an arbitrary pair of ELUs through a reconfigurable photonic network, which can be utilized to perform two-qubit quantum logic operation between any pair of physical qubits in the entire quantum computer. We show that this architecture can support universal, fault-tolerant quantum computation. [ABSTRACT FROM AUTHOR]

Quantum mechanical systems exhibit particle wave duality property. This duality property has been exploited for information processing. A duality quantum computer is a quantum computer on the move and passing through a multi-slits. It offers quantum wave divider and quantum wave combiner operations in addition to those allowed in an ordinary quantum computer. It has been shown that all linear bounded operators can be realized in a duality quantum computer, and a duality quantum computer with n qubits and d-slits can be realized in an ordinary quantum computer with n qubits and a qudit in the so-called duality quantum computing mode. The quantum particle-wave duality can be used in providing secure communication. In this paper, we will review duality quantum computing and duality quantum key distribution. [ABSTRACT FROM AUTHOR]

We show that all quantum gates which could be implemented by braiding of Ising anyons in the Ising topological quantum computer preserve the n-qubit Pauli group. Analyzing the structure of the Pauli group’s centralizer, also known as the Clifford group, for n≥3 qubits, we prove that the image of the braid group is a non-trivial subgroup of the Clifford group and therefore not all Clifford gates could be implemented by braiding. We show explicitly the Clifford gates which cannot be realized by braiding estimating in this way the ultimate computational power of the Ising topological quantum computer. [ABSTRACT FROM AUTHOR]

We discuss classical and quantum computations in terms of corresponding Hamiltonian dynamics. This allows us to introduce quantum computations which involve parallel processing of both: the data and programme instructions. Using mixed quantum-classical dynamics we look for a full cost of computations on quantum computers with classical terminals. [ABSTRACT FROM AUTHOR]

An error cancellation method for producing pseudo-pure states in large number qubit systems is proposed that is aimed at creating initial states asymptotically within a specified error tolerance by using a spatial averaging method. In this work, it is shown that the present method enables almost complete error cancellation and even enhances the NMR signal compared with the initial state within the initialization process itself. An implementation of this method was successfully demonstrated using a five-qubit NMR quantum computer. [ABSTRACT FROM AUTHOR]

We demonstrate process characterization of basic gates of an optical cluster-state quantum computing. We present complete process tomography of a single-qubit gate and evaluate the bounds on the process fidelity of a two-qubit gate. [ABSTRACT FROM AUTHOR]

I describe the main ideas of constructive physics and its role for the probability interpretation of quantum theory. It is shown how the explicit probability space for quantum systems gives the formal representation of entanglement and decoherence. [ABSTRACT FROM AUTHOR]