Quantum NOT Gate Research Articles

Intelligent Hybrid Trading Strategies Based on Quantum-Inspired Algorithm

Investing in stocks is a common choice for financial management. Technical indicators (TIs) assist investors in determining the best trading time to make a fortune. Moving average (MA) and relative strength index (RSI) are the most common TIs. The proposed hybrid technique maximizes the capabilities of these two indicators. This study utilizes the quantum-inspired algorithm to assist effectively in searching for the optimal solution in the vast solution space. The proposed trading system contains four innovative features. First, the traditional usage restriction of MA and RSI is removed to increase their potential effectiveness and identify the most profitable trading strategy. Second, this research proposes an innovative hybrid indicator (HI) that combines MA and RSI to simultaneously achieve both benefits. HI eliminates the restriction of employing a single indicator at once. Third, an efficient quantum-inspired algorithm, the Global-best-guided Quantum-inspired Tabu Search Algorithm with Quantum NOT Gate (GNQTS), effectively and efficiently explores optimized parameters. Fourth, this study proposes 60 sliding windows to determine the optimal period for training and testing. The investment targets include well-known indices: DJIA, S&P 500, NASDAQ Composite Index, and NYA, as well as high-reputation companies on the US stock market: DJIA components. By removing the restrictions imposed by these two indicators and the use of HI, the experiment results demonstrate that GNQTS can discover optimal parameters to generate higher returns than state-of-the-art methods and buy-and-hold (B&H) strategies. The proposed hybrid strategy provides for the promising prospect of quantum-inspired applications and the utilization of multiple indicators.

Quantum Computer-Aided Design Automation

Quantum computing is an essential issue for taking advantage of quantum properties in real-world applications. Realizing quantum computing with a corresponding quantum circuit is a critical step. This study introduces the AngelQ system, which provides quantum computing-as-a-service (QCaaS) for the cloud. The AngelQ system integrates quantum design automation (QDA) to achieve quantum and reversible circuit synthesis by a quantum-inspired optimization (QiO) technique and has visualization software interfaces to verify the QiO process and the correctness of the synthesized quantum and reversible circuits. First, the proposed novel QiO method has four significant features: Adaptive strategy, quantum-Not gate, update mechanism by Global solutions, and Entanglement Local search, named Angel QiO. which is a flexible technique to realize various circuits under different gate libraries with a few alterations. Angel QiO can construct diversified function-equivalent circuits to assess the circuit composition and boost the development of circuit synthesis. Second, researchers can observe the QiO algorithm process and inspect the intermediate result formula through AngelQ system’s visualization interface to further adjust the parameters and improve the performance. Moreover, it benefits beginners’ learning and adds convenience to education. In summary, the AngelQ system can extend and facilitate the future design and automation of quantum computing.

QEGWO: Energy-Efficient Clustering Approach for Industrial Wireless Sensor Networks Using Quantum-Related Bioinspired Optimization

Compared with conventional wireless sensor networks (WSNs), industrial WSNs (IWSNs) have stricter requirements in real-time data transmission, energy consumption, and energy uniformity. To fulfill these requirements, a new energy-efficient clustering approach using quantum-related bioinspired optimization, i.e., quantum elite gray wolf optimization (QEGWO), is proposed to improve the performance of IWSNs. Innovatively, a new quantum operator, including quantum probability amplitude, quantum rotation gate, and quantum NOT gate, is designed in QEGWO to enhance its global search capability. This quantum operator need not query the quantum rotation angle table in updating quantum probability amplitude with the quantum rotation gate, which reduces the computational complexity of introducing quantum optimization into the clustering problem of IWSNs. Moreover, to enhance the convergence performance of the clustering algorithm, a multielite strategy is proposed to preserve the historical optimal individuals generated in the iterative process by establishing a dynamic elite pool. Compared with the state-of-the-art clustering approaches, extensive simulations in four different scenarios are carried out, and the results demonstrate that the proposed QEGWO outperforms other comparison approaches in delay, energy consumption, and energy uniformity.

A Weighted Portfolio Optimization Model Based on the Trend Ratio, Emotion Index, and ANGQTS

A financial plan is crucial due to inflation, retirement, insurance, etc., and many people choose stock trading as one part of their overall investment portfolio. Recently, the COVID-19 pandemic has affected the economy and has had a significant impact on the stock market. The task of optimizing the portfolio to have a stable return and lower its overall risk becomes an important and emerging topic in today’s stock market. Therefore, this paper proposes a novel weighted portfolio optimization model based on the trend ratio and emotion index to comprehensively consider the volatility of the portfolio and more accurately evaluate the performance of portfolios than the classical indicator, the Sharpe ratio. Then, global-best guided quantum-inspired tabu search with a self-adaptive strategy and quantum-NOT gate (ANGQTS) which has better search ability than traditional optimization algorithm, is proposed to construct portfolios with stable upside trends efficiently and automatically. In order to dynamically suit such changeable stock markets, the proposed model adopts the sliding window mechanism. The proposed method is applied to the U.S. stock market. Compared with traditional methods and Dow Jones Industrial Average index, the proposed model shows more promising experimental results. Moreover, the proposed method derives better performance in both the downward crisis at the first outbreak of COVID-19 and the soaring trend in the stock market.

IBM Small-Scale Superconducting Quantum Computer Not Gate Error Test

Quantum NOT gates play an important role in the process of quantum information conversion. However, when the X-gate operation is executed on a real quantum computer, there is a large deviation between the actual operation result and the theory, which will lead to inaccurate results when the quantum algorithm containing the X-gate operation is executed. In order to facilitate users to understand the error fluctuations of the X gate in time before executing the quantum algorithm containing the X gate operation on the IBM quantum cloud platform, this paper proposes a method to measure the X gate error. By measuring the X-gate error of four small-scale superconducting quantum computers on the back end of the IBM quantum cloud platform, analyze the degree of fluctuation of the actual measurement value of the quantum device; at the same time, under different execution times shots, the influence of the X-gate test is analyzed. The test results show that the measured value of each qubit of different quantum devices fluctuates to different degrees; the execution times of shots are different, and the test results of X-gate error will be affected to different degrees. This test method helps users select the optimal performance of the qubits before executing quantum algorithms with X gate on IBM's small-scale quantum computers.

Superconductor qubits hamiltonian approximations effect on quantum state evolution and control

Microwave IQ-mixer controllers are designed for the three approximated Hamiltonians of charge, phase and flux qubits and the controllers are exerted both on approximate and precise quantum system models. The controlled qubits are for the implementation of the two quantum-gates with these three fundamental types of qubits, Quantum NOT-gate and Hadamard-gate. In the charge-qubit, for implementation of both gates, in the approximated and precise model, we observed different controlled trajectories. But fortunately, applying the controller designed for the approximated system over the precise system leads to the passing of the quantum state from the desired state sooner that the expected time. Phase-qubit and flux qubit have similar behaviour under the control system action. In both of them, the implementation of NOT-gate operation led to same trajectories which arrive at final goal state at different times. But in both of those two qubits for implementation of Hadamard-gate, desired trajectory and precise trajectory have some angle of deviation, then by exerting the approximated design controller to precise system, it caused the quantum state to approach the goal state for Hadamard gate implementation, and since the quantum state does not completely reach the goal state, we can not obtain very high gate fidelity.

Portfolio Optimization in Both Long and Short Selling Trading Using Trend Ratios and Quantum-Inspired Evolutionary Algorithms

Stock selection is the first problem that investors encounter when investing in the stock market and is paramount. The Sharpe ratio is a common assessment strategy. However, the Sharpe ratio considers an uptrend portfolio high risk because it assesses portfolio risk using standard deviations. Hence, we propose a novel investment strategy, namely, the trend ratio, to assess portfolio risk more accurately by the portfolio trend line. Thus, the uptrend portfolio is not considered high risk and is more consistent with the psychology of investors. In addition to normal trading (long selling), short selling is another common trading method. Short selling is borrowing stocks from stock vendors to sell and then repaying the stock at a lower price to make a profit. This paper proposes investing simultaneously in normal trading and short selling by a trend ratio, which can further increase investment profits and spread risks. This paper also adds certificates of deposit as a portfolio choice to ensure that investors can still make profits. This paper utilizes the global quantum-inspired tabu search algorithm with a quantum NOT-gate (GNQTS) to effectively find the best combination of stocks. To avoid the overfitting problem, this paper employs a sliding window. Specifically, this paper combines the trend ratio, GNQTS, short selling with certificates of deposit, and sliding windows to perform the stock selection. The experimental results are promising, with our proposed method having better performance than the Sharpe ratio. Furthermore, the experimental results show that both long selling and short selling investments can increase the performance.

Energy Levels in a Single-Electron Quantum Dot with Hydrostatic Pressure

In this article we present a study of the effects of hydrostatic pressure on the energy levels of a quantum dot with an electron. A quantum dot is modeled using an infinite potential well and a two-dimensional harmonic oscillator and solved through the formalism of second quantization. A scheme for the implementation of a quantum NOT gate controlled with hydrostatic pressure is proposed.

Demonstration of superadiabatic population transfer in superconducting qubit**Project supported by the National Key Basic Research and Development Program of China (Grant No. 2016YFA0301802) and the National Natural Science Foundation of China (Grant Nos. 11274156, 11504165, 11474152, and 61521001).

We implemented the superadiabatic population transfer within the nonadiabatic regime in a two-level superconducting qubit system. To realize the superadiabatic procedure, we added an additional term in the Hamiltonian, introducing an auxiliary counter-diabatic field to cancel the nonadiabatic contribution in the evolution. Based on the superadiabatic procedure, we further demonstrated quantum Phase and NOT gates. These operations, which possess both of the fast and robust features, are promising for quantum informationprocessing.

A quantum encoding bat algorithm for uninhabited combat aerial vehicle path planning

Uninhabited combat aerial vehicle (UCAV) path planning aims to obtain an optimal or near-optimal flight path considering the different kinds of threats and constraints in the combat field. This paper proposes a novel quantum encoding bat algorithm (QBA) for solving the path planning of UCAV. Using quantum rotation and quantum NOT gate are implemented to change the basic qubit states and to enhance global search capability. The QBA can find a feasible and global path for the UCAV to avoid the threats and constraints. The experimental results show that the proposed QBA algorithm is an effective and feasible method in solving UCAV path planning problem than some well-known algorithms.

Dynamics of observables and exactly solvable quantum problems: Using time-dependent density-functional theory to control quantum systems

We use analytic (current) density-potential maps of time-dependent (current) density functional theory (TD(C)DFT) to inverse engineer analytically solvable time-dependent quantum problems. In this approach the driving potential (the control signal) and the corresponding solution of the Schr\"odinger equation are parametrized analytically in terms of the basic TD(C)DFT observables. We describe the general reconstruction strategy and illustrate it with a number of explicit examples. First we consider the real space one-particle dynamics driven by a time-dependent electromagnetic field and recover, from the general TDDFT reconstruction formulas, the known exact solution for a driven oscillator with a time-dependent frequency. Then we use analytic maps of the lattice TD(C)DFT to control quantum dynamics in a discrete space. As a first example we construct a time-dependent potential which generates prescribed dynamics on a tight-binding chain. Then our method is applied to the dynamics of spin-1/2 driven by a time dependent magnetic field. We design an analytic control pulse that transfers the system from the ground to excited state and vice versa. This pulse generates the spin flip thus operating as a quantum NOT gate.

NOT and CNOT gates for photon logical qubits on different frequency states

Starting from Hamiltonian of three level atom interacting with photons, we calculate effective Hamiltonian by Schrieffer-Wolff transformation. We obtain the operation of photon frequency conversion solving appropriate Schrodinger equation. Based on this operation, an efficient protocol is proposed for implementing quantum NOT and CNOT gates for applications in quantum information processing.

Simulation of a quantum NOT gate for a single qutrit system

A three-level system based an a three-level atom interacting with a detuned cavity is considered. Because of the fact that the three-level atom defines a total normalized state composed of superposition of three different single-level states, it is assumed that such a system implements a qutrit. In order to achieve a quantum NOT gate for a single qutrit, the respective Schrodinger equation is solved numerically within a two-photon rotating wave approximation. For small values of one-photon detuning, there appear decoherence effects. Meanwhile, for large values of one-photon detuning, an ideal quantum NOT gate for a single qutrit is achieved. An expression for the execution time of the quantum NOT gate for a single qutrit as a function of the one-photon detuning is found.

Times of execution of the quantum NOT gate

It is generally believed that entanglement speeds up Quantum Information Processing (QIP). How- ever, we prove that for a system of two interacting qubits through a XXZ Hamiltonian which are maximally entan- gled it is not possible to execute a quantum NOT gate operating on one of these two qubits. The interaction between the two qubits means presence of noise in one of them. If the two interacting qubits are not entangled, the times of execution of the quantum NOT gate oper- ating on one of the two qubits are not small enough. Since the times of execution of the quantum NOT gate operating on one of the two interacting qubits is extremely large, we conclude that the execution of the quantum NOT gate operating on one of two interacting qubits is not possible.

Information Technology in an Improved Quantum Genetic Algorithm Based on Dynamic Adjustment of Quantum Rotation Angle

To overcome the shortcomings of precocity and being easily trapped into local optimum of the standard quantum genetic algorithm (QGA) , Information Technology in An Improved Quantum Genetic Algorithm based on dynamic adjustment of the quantum rotation angle of quantum gate (DAAQGA) was proposed. Mutation operation using the quantum not-gate is also introduced to enhance the diversity of population. Chaos search are also introduced into the modified algorithm to improve the search accuracy. Simulation experiments have been carried and the results show that the improved algorithm has excellent performance both in the preventing premature ability and in the search accuracy.

New scheme on how to realize quantum NOT gate

Recently, some schemes on how to realize quantum NOT gate have been reported. In this paper, we theoretically propose a new scheme by means of quantum theory. Here we use a quantum coin as a quantum NOT gate and its logic function is realized by the quantum game theory. In our schemes, classical noise does not disturb the realization of quantum NOT gate.

A unified quantum NOT gate

We study the universal quantum NOT machine (approximate) when the quantum state lies between two latitudes on the Bloch sphere and present an analytical formula for the optimized 1-to-M quantum NOT gate. Our result generalizes previous results concerning a quantum NOT gate for a quantum state distributed uniformly on the whole Bloch sphere as well as for the phase-covariant quantum state. We have also shown that such a 1-to-M optimized NOT gate can be implemented using a sequential generation scheme via matrix product states.

Relation between quantum NOT gate speed and asymmetry of the potential of RF-SQUID

This paper investigates the relationship between the speed of a quantum not gate and the asymmetry of the potential in an interactive system formed by a two-level RF-SQUID qubit and a classical microwave pulse. The RF-SQUID is characterized by an asymmetric double well potential which gives rise to diagonal matrix elements that describe the interaction of the SQUID with the microwave pulse. And the diagonal matrix elements account for the interaction of the microwave pulse with the SQUID. The results indicate that, when the angular frequency of the microwave field is chosen as near resonate with the transition |0〉 ↔ |1〉0, i.e. ω1 - ω0 ≈ ωm, (1) the gate speed is decided by three factors, the Rabi frequency, the difference of the diagonal matrix elements between the two levels, and the angular frequency of the applied microwave pulse ωm; (2) the gate speed descends when the asymmetry of the potential is considered.

INVESTIGATION COMPARISON ON THE GATE SPEED OF THREE-LEVEL AND TWO-LEVEL QUANTUM NOT GATES WITH ASYMMETRIC POTENTIAL OF rf-SQUID

We investigate the relation between the speed of quantum NOT gate and the asymmetry or detuning of the potential in system of the interaction of a two-level rf-SQUID qubit with a classical microwave pulse. The rf-SQUID is characterized by an asymmetric double well potential that gives rise to diagonal matrix elements. Then in resonance, we compare the gate speeds for three-level and two-level quantum NOT gates. We show that in general, a three-level gate is much faster than the conventional two-level gate.

Conservation-law-induced quantum limits for physical realizations of the quantum NOT gate

In recent investigations, it has been found that conservation laws generally lead to precision limits on quantum computing. Lower bounds of the error probability have been obtained for various logic operations from the commutation relation between the noise operator and the conserved quantity or from the recently developed universal uncertainty principle for the noise-disturbance trade-off in general measurements. However, the problem of obtaining the precision limit to realizing the quantum NOT gate has eluded a solution from these approaches. Here, we develop a method for this problem based on analyzing the trace distance between the output state from the realization under consideration and the one from the ideal gate. Using the mathematical apparatus of orthogonal polynomials, we obtain a general lower bound on the error probability for the realization of the quantum NOT gate in terms of the number of qubits in the control system under conservation of the total angular momentum of the computational qubit plus the control system along the direction used to encode the computational basis. The lower bound turns out to be more stringent than one might expect from previous results. Our method is expected to lead to more accurate estimates for physical realizations of variousmore » types of quantum computations under conservation laws and to contribute to related problems such as the accuracy of programmable quantum processors.« less