Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session M40: Quantum AlgorithmsFocus Recordings Available
|
Hide Abstracts |
Sponsoring Units: DQI Chair: Junyu Liu, University of Chicago Room: McCormick Place W-196B |
Wednesday, March 16, 2022 8:00AM - 8:12AM |
M40.00001: Statistical Approach to Quantum Phase Estimation Yuchen Wang, Alexandria Moore, Zixuan Hu, Sabre Kais, Andrew M Weiner We introduce a new statistical and variational approach to the phase estimation algorithm (PEA). Un-like the traditional and iterative PEAs which return only an eigenphase estimate, the proposed methodcan determine any unknown eigenstate-eigenphase pair from a given unitary matrix utilizing a simplifiedversion of the hardware intended for the Iterative PEA (IPEA). This is achieved by treating the probabilistic output of an IPEA-like circuit as an eigenstate-eigenphase proximity metric, using this metric toestimate the proximity of the input state and input phase to the nearest eigenstate-eigenphase pair andapproaching this pair via a variational process on the input state and phase. This method may searchover the entire computational space, or can efficiently search for eigenphases (eigenstates) within somespecified range (directions), allowing those with some prior knowledge of their system to search for particular solutions. We show the simulation results of the method with the Qiskit package on the IBM Qplatform and on a local computer. |
Wednesday, March 16, 2022 8:12AM - 8:24AM |
M40.00002: Demonstrating a Quantum Permutation Algorithm with Higher Qubit (up to 16-qubit) Near-term Intermediate Scale Quantum Processors Ashley Blackwell, Onur Danaci, Thomas A Searles Quantum computation is an emerging field that harnesses quantum mechanical phenomena through the manipulation of qubits. The way in which a qubit is manipulated is by quantum algorithms or step-by-step commands to change the state of the qubit and gives probabilities of a particular problem's outcome. One example of a quantum algorithm for a such system is the quantum permutation algorithm which determines the parity of a given cyclic permutation in a single measurement. Previously shown by Yalcinkaya and Gedik (2017) this algorithm can be optimized by minimizing the number of required quantum gates by replacing the quantum Fourier transform (QFT) and its inverse with simpler transformations. We are interested in expanding this to higher qubit numbers using cloud accessed near-term intermediate scale quantum processors through the IBM Quantum Experience. The goal of this work is to implement a modified quantum permutation algorithm using 16 qubits using Qiskit, IBM's qasm simulator and NISQ hardware with various qubit mappings. We found that increasing the qubit number shows improvement over previous studies utilizing QFTs. In the future, we plan to look at ways of applying pulse level control to this algorithm to further show quantum advantage using available NISQ hardware. |
Wednesday, March 16, 2022 8:24AM - 8:36AM Withdrawn |
M40.00003: Nearly Optimal Quantum Algorithm for Estimating Multiple Expectation Values William J Huggins, Nathan Wiebe, Jarrod McClean, Thomas E O'Brien, Kianna Wan, Ryan Babbush Many quantum algorithms involve the evaluation of expectation values with respect to some pure state. Optimal strategies for estimating a single expectation value to within a precision ε are known, requiring a number of calls to a state preparation oracle proportional to ε-1 in the asymptotic limit. In this paper, we address the task of evaluating the expectation values of M different observables with the same ε-1 scaling in the desired precision. We provide an approach that requires a number of calls to oracle calls that scales as M1/2ε-1(neglecting logarithmic factors). Furthermore, we show that this scaling is optimal, even in the special case when the operators in question commute. |
Wednesday, March 16, 2022 8:36AM - 8:48AM |
M40.00004: Simulating Large PEPs Tensor Networks on Small Quantum Devices Ian MacCormack, Alexey Galda, Adam Lyon We systematically map low-bond-dimension PEPs tensor networks to quantum circuits. By measuring and reusing qubits, we demonstrate that a simulation of an N×M square-lattice PEPs network, for arbitrary M, of bond dimension 2 can be performed using N+2 qubits. We employ this approach to calculate the values of a long-range loop observable in the topological Wen plaquette model by mapping a 3×3 PEPs tensor network to a 5-qubit quantum circuit and executing it on the Honeywell System Model H1-1 trapped-ion device. We find that, for this system size, the noisy observable values are sufficient for diagnosing topological vs. trivial order, as the Wen model is perturbed by a magnetic field term in the Hamiltonian. Our results serve as a proof-of-concept of the utility of the measure-and-reuse approach for simulating large two-dimensional quantum systems on small quantum devices. |
Wednesday, March 16, 2022 8:48AM - 9:00AM |
M40.00005: Quantum Simulation of Open Quantum Systems Using a Unitary Decomposition of Operators Anthony Schlimgen Because the time evolution of an open quantum system employs a non-unitary operator, the simulation of open quantum systems presents a challenge for universal quantum computers constructed from only unitary operators or gates. Here we present a general algorithm for implementing the action of any non-unitary operator on an arbitrary state on a quantum device. We show that any quantum operator can be exactly decomposed as a linear combination of at most four unitary operators. We demonstrate this method on a two-level system in both zero and finite temperature amplitude damping channels. The results are in agreement with classical calculations, showing promise in simulating non-unitary operations on intermediate-term and future quantum devices. |
Wednesday, March 16, 2022 9:00AM - 9:36AM |
M40.00006: Error mitigation and the prospect of near term applications Invited Speaker: Kristan Temme Near-term applications of early quantum devices, such as quantum simulations, rely on accurate estimates of expectation values to become relevant. Decoherence and gate errors lead to wrong estimates. This problem was, at least in theory, remedied with the advent of quantum error correction. However, the overhead that is needed to implement a fully fault-tolerant gate set with current codes and current devices seems prohibitively large. In turn, steady progress is made in improving the quality of the quantum hardware. This leads to the question: what computational tasks could be accomplished with only limited, or no error correction? In this talk we discuss recent advances in techniques that have become known as quantum error mitigation. These methods are aimed at increasing the quality of expectation values in short-depth quantum circuits. |
Wednesday, March 16, 2022 9:36AM - 9:48AM |
M40.00007: Long-time simulations with high fidelity on quantum hardware ZOE HOLMES, Joe Gibbs, Kaitlin M Gili, Benjamin Commeau, Andrew T Arrasmith, Lukasz Cincio, Patrick J Coles, Andrew T Sornborger Moderate-size quantum computers are now publicly accessible over the cloud, opening the exciting possibility of performing dynamical simulations of quantum systems. However, while rapidly improving, these devices have short coherence times, limiting the depth of algorithms that may be successfully implemented. Here we demonstrate that, despite these limitations, it is possible to implement long-time, high fidelity simulations on current hardware. Specifically, we simulate an XY-model spin chain on the Rigetti and IBM quantum computers, maintaining a fidelity of at least 0.9 for over 600 time steps. This is a factor of 150 longer than is possible using the iterated Trotter method. Our simulations are performed using a new algorithm that we call the fixed state Variational Fast Forwarding (fsVFF) algorithm. This algorithm decreases the circuit depth and width required for a quantum simulation by finding an approximate diagonalization of a short time evolution unitary. Crucially, fsVFF only requires finding a diagonalization on the subspace spanned by the initial state, rather than on the total Hilbert space as with previous methods, substantially reducing the required resources. We further demonstrate the viability of fsVFF through large numerical implementations of the algorithm, as well as an analysis of its noise resilience and the scaling of simulation errors. |
Wednesday, March 16, 2022 9:48AM - 10:00AM |
M40.00008: Algorithmic quantum-state generation for quantum simulation of a quantum field theory Mohsen Bagherimehrab, Yuval R Sanders, Dominic W Berry, Gavin K Brennen, Barry C Sanders We establish two quasilinear quantum algorithms, one Fourier-based and the other wavelet-based, for generating an approximation for the ground state of a quantum field theory (QFT). |
Wednesday, March 16, 2022 10:00AM - 10:12AM |
M40.00009: Ancilla-free implementation of POVM measurements for near-term quantum algorithms Francesco Tacchino, Laurin Fischer, Daniel Miller, Panagiotis Kl. Barkoutsos, Daniel J Egger, Ivano Tavernelli Positive Operator-Valued Measures (POVMs) describe a class of generalized quantum measurements offering conceptual and operational advantages over the usual computational basis readout. In particular, Informationally Complete (IC) POVMs can be employed for efficient partial state tomography and to measure observable expectation values with performances that surpass those of standard operator averaging methods, as recently demonstrated by García-Pérez et al. [1]. In this work, we propose an ancilla-free scheme for the practical implementation of POVM readout in IBM superconducting processors. This method alleviates the main drawback of traditional IC-POVM measurement schemes, which typically require the use of accessory qubit resources and may thus be demanding in terms of device size and connectivity. We present experimental results for proof-of-principle applications to paradigmatic quantum information tasks, along with systematic studies of control pulse sequences and hardware requirements. [1] G. García-Pérez et al., arXiv:2104.00569 (to appear in PRX Quantum) |
Wednesday, March 16, 2022 10:12AM - 10:24AM |
M40.00010: Efficient Quantum Circuit Preparation of Resonating Valence Bond States Byungmin Kang, Vito W Scarola, Kwon Park When studying strongly correlated systems using quantum circuits, it is important to prepare good initial states from which the target many-body states can easily be accessed. Here, we discuss an efficient quantum circuit preparation of the resonating valence bond (RVB) state, which plays an essential role in understanding the high-Tc superconductivity and the spin liquid physics. It is known that the RVB state is given by the Gutzwiller projection of a Bardeen-Cooper-Schrieffer (BCS) state for which an efficient quantum circuit construction is known. However, since the overlap between the RVB state and the BCS state decays exponentially in the system size, naive implementation of the Gutzwiller projection as projective measurements in quantum circuit would require exponentially many repetitions in order to obtain the RVB state. In this talk, we discuss how to systematically amplify the amplitude associated with the RVB state in the BCS state using a recently developed amplitude amplification technique. Following our construction, one can construct a quantum circuit for the RVB state with an arbitrarily high success probability. |
Wednesday, March 16, 2022 10:24AM - 10:36AM |
M40.00011: Quantum Signal Processing and optimal Hamiltonian simulation using Rydberg atoms Sina Zeytinoglu, Sho Sugiura Quantum algorithms promise an immense improvement to our current information processing capabilities by utilizing the interference phenomena in an exponentially large Hilbert space. However, the large size of the Hilbert space also poses a crucial challenge to the experimentalists, who strive to design control sequences that navigate this space using only semiclassical fields. A set of novel frameworks consisting of Linear Combination of Unitaries (LCU) and Quantum Signal Processing (QSP) provide effective solutions to this control problem by constructing ever more complicated operators starting from simply implemented multi-qubit Paulis. Here, we introduce an efficient and scalable toolbox for realizing these solutions on the Rydberg atom platform. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700