Article
Quantum Science & Technology
Niladri Gomes, Anirban Mukherjee, Feng Zhang, Thomas Iadecola, Cai-Zhuang Wang, Kai-Ming Ho, Peter P. Orth, Yong-Xin Yao
Summary: The AVQITE approach introduces an adaptive variational quantum imaginary time evolution method that efficiently represents ground states for interacting Hamiltonians on near-term quantum computers. By iteratively expanding the variational ansatz to keep the McLachlan distance below a chosen threshold, AVQITE ensures the state can follow the quantum imaginary time evolution path in the system Hilbert space. This method has been successfully applied to prepare ground states of molecules like H-4, H2O, and BeH2, showing compact variational ansatze and ground state energies within chemical accuracy.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
Article
Quantum Science & Technology
Kubra Yeter-Aydeniz, Bryan T. Gard, Jacek Jakowski, Swarnadeep Majumder, George S. Barron, George Siopsis, Travis S. Humble, Raphael C. Pooser
Summary: Quantum chemistry serves as a key benchmark for current and future quantum computer performance, with state-of-the-art methods outlined for achieving chemical accuracy on NISQ devices. These methods include extending variational eigensolvers with symmetry preserving Ansatze and using quantum imaginary time evolution and Lanczos as complementary methods. A new error mitigation method is also highlighted, demonstrating rapid advancements in electronic structure calculations.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
Article
Chemistry, Multidisciplinary
Matthias Koch, Oliver Schaudt, Georg Mogk, Thomas Mrziglod, Helmut Berg, Michael Edmund Beck
Summary: Being able to predict molecular properties and interactions is a major interest in academia and industry. However, classical algorithms are limited by the complexity of strongly correlated molecular systems. Quantum computation has the potential to revolutionize molecular simulations, but current quantum computers are not capable enough for handling complex molecular systems. In this paper, we propose a variational ansatz for today's noisy quantum computers to calculate the ground state using imaginary time evolution, which can be implemented on a quantum computer by linear decomposition and Taylor series expansion.
Article
Quantum Science & Technology
Rizwanul Alam, George Siopsis, Rebekah Herrman, James Ostrowski, Phillip C. Lotshaw, Travis S. Humble
Summary: We propose an efficient method for solving the MaxCut problem using quantum imaginary time evolution (QITE). By utilizing a linear Ansatz for unitary updates and an initial state with no entanglement, along with an imaginary-time-dependent Hamiltonian, we achieve high-performance convergence to the maximum solution for the MaxCut problem in various randomly selected graphs. Our algorithm outperforms classical algorithms, such as the greedy and Goemans-Williamson algorithms, and we introduce the overlap of the QITE algorithm's final state with the ground state as a unique performance metric, highlighting its quantum advantage.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Optics
Pejman Jouzdani, Calvin W. Johnson, Eduardo R. Mucciolo, Ionel Stetcu
Summary: This study proposes an alternative approach to implement imaginary time evolution (ITE) by using an orthogonal basis set to efficiently represent propagated states. The number of basis states needed can be controlled by precision and time increment, making the algorithm polynomial in the number of qubits. The algorithm is useful for studying nonlocal systems.
Article
Computer Science, Artificial Intelligence
Ivan Zelinka, Lumir Kojecky, Marek Lampart, Jana Nowakova, Jan Plucar
Summary: In this paper, the possibilities of designing quantum computing circuits using a specific swarm intelligence algorithm, iSOMA, are demonstrated through three experiments. The simulations are based on a simple sample of a quantum computing circuit from the Qiskit environment and compared with the results of the three mentioned experiments. It is observed that iSOMA shows a high degree of creativity in finding arbitrary functional solutions with minimal constraints on the circuit's design. Additionally, iSOMA is capable of finding efficient solutions by avoiding unnecessary qubit usage through the addition of redundant qubits and fixing the measurement gates. The results indicate the successful application of evolutionary algorithms in designing complex quantum circuits.
APPLIED SOFT COMPUTING
(2023)
Article
Computer Science, Information Systems
Giovanni Acampora, Autilia Vitiello
Summary: This study introduces a new evolutionary algorithm utilizing an actual quantum processor, which employs quantum phenomena to achieve significant speed-up in computation. By implementing quantum concepts such as quantum chromosome and entangled crossover, the proposed algorithm efficiently executes genetic evolution on quantum devices to converge towards proper sub-optimal solutions of a given optimization problem. The experimental results show that the synergy between quantum and evolutionary computation leads to a promising bio-inspired optimization strategy.
INFORMATION SCIENCES
(2021)
Article
Physics, Multidisciplinary
Nhat A. Nghiem, Tzu-Chieh Wei
Summary: This study leverages techniques from the HHL algorithm, classical power, and Krylov subspace method to devise a simple quantum algorithm for estimating the largest eigenvalues in magnitude of a Hermitian matrix. Our quantum algorithm offers significant speedup compared to classical algorithms in terms of matrix size.
Article
Quantum Science & Technology
Tong Liu, Jin-Guo Liu, Heng Fan
Summary: Simulation of quantum materials is a significant application of quantum computers. Implementing nonunitary operations, which are widely used in classical approaches, on a quantum computer requires special design. By applying Grover's algorithm, a probabilistic method of implementing nonunitary operations can be extended to increase success probability without fidelity decreasing, and this method can be applied to problems such as imaginary time evolution and contraction of tensor networks on a quantum computer.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Chemistry, Multidisciplinary
Zhijie Yang, Qiang Zhuang, Yong Yan, Guillermo Ahumada, Bartosz A. Grzybowski
Summary: Using amphiphilic Janus Au/Fe3O4 nanoparticles covered aqueous droplets suspended in an organic phase as building blocks, the droplet-based electronic circuitry displays rectification ability and can function as AND or OR gates or inversors when combined with salt-containing resistor droplets.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Mathematics
Kamil Khadiev, Artem Ilikaev, Jevgenijs Vihrovs
Summary: This study investigates algorithms for solving string problems, including string sorting, most frequent string search, and intersection searching of string sequences. Quantum algorithms are found to outperform classical algorithms in terms of complexity for each of these problems.
Article
Multidisciplinary Sciences
Raja Selvarajan, Vivek Dixit, Xingshan Cui, Travis S. Humble, Sabre Kais
Summary: The road to quantum computing has been accelerated by the promises of Shor's algorithm, but has not yet been realized due to noisy qubits and lack of robust error correction schemes. An alternative method using variational imaginary time evolution is explored, showing promise for prime factorization. This method scales circuits based on the bit-length of the number and circuit depth, successfully factoring numbers greater than previously achieved on IBMQ hardware.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Multidisciplinary
Alexandria J. Moore, Yuchen Wang, Zixuan Hu, Sabre Kais, Andrew M. Weiner
Summary: The new method introduced in this study can determine any unknown eigenstate-eigenphase pair from a given unitary matrix using simplified hardware, and it can search over the entire computational space for eigenphases (eigenstates) or efficiently search for eigenphases (eigenstates) within a specified range.
NEW JOURNAL OF PHYSICS
(2021)
Article
Chemistry, Physical
Pablo E. Videla, Victor S. Batista
Summary: An exact path-integral formalism is introduced for calculating multi-time quantum correlation functions, using canonical averages over ring-polymer dynamics in imaginary time. The formulation exploits the symmetry of path integrals with respect to permutations in imaginary time, expressing correlations as products of imaginary-time-translation-invariant phase-space functions coupled through Poisson bracket operators. The method recovers the classical limit of multi-time correlation functions and provides an interpretation of quantum dynamics in terms of interfering trajectories of the ring-polymer in phase space. The introduced phase-space formulation provides a rigorous framework for the future development of quantum dynamics methods that exploit the invariance of imaginary time path integrals to cyclic permutations.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Quantum Science & Technology
Shi-Ning Sun, Mario Motta, Ruslan N. Tazhigulov, Adrian T. K. Tan, Garnet Kin-Lic Chan, Austin J. Minnich
Summary: Employing the quantum imaginary time evolution (QITE) algorithm on five-qubit IBM Quantum devices, we have successfully calculated finite-temperature properties of spin systems with up to four sites, including energy, correlation functions, and excitation spectra. Our work demonstrates that the ansatz-independent QITE algorithm is capable of computing diverse finite-temperature observables on near-term quantum devices, thanks to algorithmic improvements such as exploiting symmetries, circuit optimization, and error-mitigation techniques.
Article
Physics, Multidisciplinary
Kubra Yeter-Aydeniz, George Siopsis, Raphael C. Pooser
Summary: By utilizing a quantum computer, the simulation of one-particle propagation and two-particle scattering in the one-dimensional transverse Ising model was successfully achieved. The experimental results obtained were in good agreement with those obtained using exact diagonalization, showing the potential for near-term quantum computers to simulate quantum field theories.
NEW JOURNAL OF PHYSICS
(2021)
Article
Quantum Science & Technology
Rebekah Herrman, James Ostrowski, Travis S. Humble, George Siopsis
Summary: This study identifies how the structure of problem instances can be used to determine lower bounds for the circuit depth required for each iteration of QAOA, and examines the relationship between problem structure and a variety of combinatorial optimization problems. By analyzing the scaling of circuit depth, it is suggested that MaxCut, MaxIndSet, and some instances of vertex covering and Boolean satisfiability problems are suitable for QAOA approaches, while knapsack and traveling salesperson problems are not.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Physics, Multidisciplinary
Siddhartha Das, George Siopsis
Summary: The article discusses quantum position verification (QPV) protocols, pointing out the insecurity of QPV protocols using single-qubit states, introducing practically secure QPV protocols, and presenting a cheating strategy.
NEW JOURNAL OF PHYSICS
(2021)
Article
Quantum Science & Technology
Rebekah Herrman, Lorna Treffert, James Ostrowski, Phillip C. Lotshaw, Travis S. Humble, George Siopsis
Summary: The performance of QAOA algorithm on MaxCut problem is studied under different graph characteristics, revealing correlations with graph symmetries, odd cycles, and density. Data analysis demonstrates some factors that can predict the success of QAOA.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Quantum Science & Technology
Kubra Yeter-Aydeniz, Shikha Bangar, George Siopsis, Raphael C. Pooser
Summary: In this study, we calculate the energy levels and transition probabilities of a neutrino system using the quantum Lanczos algorithm implemented on IBM Q quantum computer hardware. By simplifying the system Hamiltonian and using the Trotterization method, we achieve good agreement with exact results.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Quantum Science & Technology
Shane Thompson, George Siopsis
Summary: This article investigates the phase transition problem in the Schwinger model, performs a quantum computation using a momentum space formalism on a lattice, and obtains a result for the critical point around 0.32, which is in good agreement with the classical numerical result.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Quantum Science & Technology
Rizwanul Alam, George Siopsis, Rebekah Herrman, James Ostrowski, Phillip C. Lotshaw, Travis S. Humble
Summary: We propose an efficient method for solving the MaxCut problem using quantum imaginary time evolution (QITE). By utilizing a linear Ansatz for unitary updates and an initial state with no entanglement, along with an imaginary-time-dependent Hamiltonian, we achieve high-performance convergence to the maximum solution for the MaxCut problem in various randomly selected graphs. Our algorithm outperforms classical algorithms, such as the greedy and Goemans-Williamson algorithms, and we introduce the overlap of the QITE algorithm's final state with the ground state as a unique performance metric, highlighting its quantum advantage.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Optics
Nora M. Bauer, Elias Kokkas, Victor Ale, George Siopsis
Summary: We study the emergence of topological matter in two-dimensional systems of neutral Rydberg atoms in Ruby lattices. While Abelian anyons have been predicted in such systems, non-Abelian anyons, which would form a substrate for fault-tolerant quantum computing, have not been generated. We obtain the topologically distinct ground states of the system numerically using the infinite Density Matrix Renormalization Group technique. We discuss how these topological states can be created using ancilla atoms of a different type. We show that a system with 2N + 2 punctures and an equal number of ancilla atoms leads to N logical qubits whose Hilbert space is determined by a set of stabilizing conditions on the ancilla atoms. Quantum gates can be implemented using a set of gates acting on the ancilla atoms that commute with the stabilizers and realize the braiding group of non-Abelian Ising anyons.
Proceedings Paper
Computer Science, Theory & Methods
Shikha Bangar, George Siopsis, Kubra Yeter-Aydeniz
Summary: The study explores the potential of CV quantum computing in building neural network models and proposes a hybrid quantum-classical neural network protocol that can be experimentally implemented. By using Gaussian gates and ancillary qumodes to achieve nonlinearity, the protocol overcomes the experimental difficulties and successfully addresses machine learning problems like curve fitting and binary classification.
2022 IEEE INTERNATIONAL CONFERENCE ON QUANTUM COMPUTING AND ENGINEERING (QCE 2022)
(2022)
Article
Optics
Brian J. Rollick, George Siopsis, Bing Qi
Summary: Researchers propose a dynamic attenuation scheme to monitor channel transmittance and introduce suitable attenuation at the measurement device, leading to improved performance of MDI QKD over free-space channels.
Article
Optics
Kubra Yeter-Aydeniz, Eleftherios Moschandreou, George Siopsis
Summary: In this study, we calculate the energy levels and eigenstates of an interacting scalar quantum field theory using a continuous-variable version of the quantum imaginary-time evolution algorithm. Our results obtained from Xanadu's Strawberry Fields photonic simulator show excellent agreement with exact calculations. Furthermore, we propose an experimental setup that can be realized using existing technology.
Article
Optics
Eleftherios Moschandreou, Brian J. Rollick, Bing Qi, George Siopsis
Summary: In free-space quantum key distribution (QKD) under turbulent conditions, rejecting received bits below a transmittance threshold can mitigate intensity fluctuations, reducing overall error rate and increasing secure key rate. Through the implementation of the prefixed-threshold real-time selection (P-RTS), higher secure key rates can be achieved for a wide range of atmospheric channel parameters. Additionally, the P-RTS method shows potential for determining an optimal selection threshold even with imperfect knowledge of channel transmittance distribution parameters.
Article
Quantum Science & Technology
Kubra Yeter-Aydeniz, Bryan T. Gard, Jacek Jakowski, Swarnadeep Majumder, George S. Barron, George Siopsis, Travis S. Humble, Raphael C. Pooser
Summary: Quantum chemistry serves as a key benchmark for current and future quantum computer performance, with state-of-the-art methods outlined for achieving chemical accuracy on NISQ devices. These methods include extending variational eigensolvers with symmetry preserving Ansatze and using quantum imaginary time evolution and Lanczos as complementary methods. A new error mitigation method is also highlighted, demonstrating rapid advancements in electronic structure calculations.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
