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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]

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]

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]

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]

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]

This study considers implementations of error correction in a simulation language on a classical computer. Error correction will be necessarily in quantum computing and quantum information. We will give some examples of the implementations of some error correction codes. These implementations will be made in a more general quantum simulation language on a classical computer in the language Mathematica. The intention of this research is to develop a programming language that is able to make simulations of all quantum algorithms and error corrections in the same framework. The program code implemented on a classical computer will provide a connection between the mathematical formulation of quantum mechanics and computational methods. This gives us a clear uncomplicated language for the implementations of algorithms. [ABSTRACT FROM AUTHOR]

Due to the increasing computing power of the graphics processing units (GPU), they are becoming more and more popular when solving general purpose algorithms. As the simulation of quantum computers results on a problem with exponential complexity, it is advisable to perform a parallel computation, such as the one provided by the SIMD multiprocessors present in recent GPUs. In this paper, we focus on an important quantum algorithm, the quantum Fourier transform (QTF), in order to evaluate different parallelization strategies on a novel GPU architecture. Our implementation makes use of the new CUDA software/hardware architecture developed recently by NVIDIA. [ABSTRACT FROM AUTHOR]

Quantum versions of random walks have diverse applications that are motivating experimental implementations as well as theoretical studies. Recent results showing quantum walks are "universal for quantum computation" relate to algorithms, to be run on quantum computers. We consider whether an experimental implementation of a quantum walk could provide useful computation before we have a universal quantum computer. [ABSTRACT FROM AUTHOR]

The article focuses on the goal of the Grover quantum algorithm which is to find an item in a randomly ordered database. The advantage of Grover algorithm is rooted in apply a cleverly constructed Grover gate to a convenient initial entangled state of n-orbit registers. Entangled states however are very sensitive to decoherence originating from the interaction of quantum computer and its environment.

In this paper a quantum computer based on the recombination processes happening in semiconductor devices is presented. A “data element” and a “computational element” are derived based on Schokley-Read-Hall statistics and they can later be used in order to manifest a simple and known quantum algorithm. Such a paradigm is shown by the application of the proposed technology onto the Shor’s period-finding algorithm. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Recently, the quantum computer (QC) using the nano-devices have significantly attracted attention, because a large-scale extention of the qubits could be easily realized in the nano-devices. However, some problems for the realization of the QC with nano-devices arise from the short decoherence time and the interaction of qubits only between nearest-neighbor qubits. Therefore, we try to design the optimal quantum circuit of the quantum Fourier transform in various network system by means of the genetic algorithm (GA). © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]