Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session W38: Control and Characterization Tools for Quantum Error MitigationFocus

Hide Abstracts 
Sponsoring Units: DQI Chair: Timothy Proctor, Sandia National Laboratories Room: 607 
Friday, March 6, 2020 8:00AM  8:12AM 
W38.00001: Demonstrating error rate homogenization using dynamically corrected gates in a trapped ion system Claire Edmunds, Cornelius Hempel, Alistair Milne, Michael Biercuk High quality, errorrobust gates are a fundamental element of scalable quantum computing architectures; however, their performance is often limited by their high sensitivity to external perturbations and imperfections in the control field. We experimentally demonstrate that replacing “primitive” physical gates with errorsuppressing, dynamically corrected gates (DCGs) can homogenize error rates across a qubit register in both space and time, in addition to reducing net error rates. 
Friday, March 6, 2020 8:12AM  8:24AM 
W38.00002: Error Mitigation Via Simulated Measurement of Stabilizers Amy Greene, Morten Kjaergaard, Mollie Schwartz, Gabriel Samach, Andreas Bengtsson, Michael O'Keeffe, Milad Marvian, Roni Winik, David K Kim, Alexander Melville, Bethany Niedzielski, Jonilyn Yoder, Danna Rosenberg, Kevin Obenland, Terry Philip Orlando, Iman Marvian, William Oliver While closedloop control is the ideal for quantum error correction, openloop techniques are more accessible given current technologies. Dynamical decoupling is the goto error mitigation technique, but many of the noise mechanisms encountered in experimental implementations, such as microwave crosstalk or coherent gate errors, are not amenable to simple dynamical decoupling schemes. An alternative technique for these errors is to simulate measurement of stabilizer operators via the stochastic application of gates from the set of stabilizers. We demonstrate the errormitigating effects of this simulated quantum measurement protocol on a small superconducting qubit processor. 
Friday, March 6, 2020 8:24AM  8:36AM 
W38.00003: SPAM Error Correction: Transition Matrix versus Quasiprobabilities Mingyu Sun, Michael Ray Geller State preparation and measurement (SPAM) errors limit the performance 
Friday, March 6, 2020 8:36AM  8:48AM 
W38.00004: Experimental Realization of Randomized Compiling for insitu Error Reduction Akel Hashim, Kasra Nowrouzi, Alexis Morvan, Ravi Kaushik Naik, John Mark Kreikebaum, Irfan Siddiqi We present work on reducing the average error during the operation of an algorithm through randomized compiling (RC) [1], which tailors arbitrary Markovian noise into stochastic Pauli errors. By compiling random singlequbit twirling gates into the bare sequence of an algorithm and averaging over many initializations of an RC circuit, the total error of an algorithm is reduced because the error per single qubit gate has been averaged into a stochastic noise channel that is independent of the gate itself. Here, we demonstrate experimental work towards implementing RC in both random circuits and quantum protocols for optimization problems. We show that RC suppresses coherent errors in a circuit and that it increases the probability of measuring the correct solution of an algorithm. 
Friday, March 6, 2020 8:48AM  9:00AM 
W38.00005: Optimizing stability and performance of cloudbased quantum systems Neereja Sundaresan, Isaac Lauer, Srikanth Srinivasan, Cindy Wang, William Landers, Michael Stuart Gordon, Douglas T. McClure Since the launch of the first fivequbit device on the IBM Q Experience platform in 2016, we have made steady increases in the number of devices available for cloud access, as well as their fidelity, stability, speed and uptime. Here we will discuss some of the challenges encountered, lessons learned, and best practices adopted in the bringup, operation, and maintenance of these devices. 
Friday, March 6, 2020 9:00AM  9:12AM 
W38.00006: Fidelity of sequences of SWAP operations in chains of multiple coupled qubits Robert Throckmorton We investigate the swapping of qubit states between neighboring qubits in a chain of multiple qubits with quasistatic noise both in the (nearestneighbor) couplings between them and in fields applied to the individual qubits. We will assume no intentionally applied fields, so that all such fields that appear are due entirely to noise. We consider chains of several different lengths and different sequences of SWAP operations (i.e., different pairs of neighboring qubits to perform the operation on and different lengths). We determine the fidelity of these sequences as a function of sequence and qubit chain length for different noise strengths. 
Friday, March 6, 2020 9:12AM  9:24AM 
W38.00007: Noiseresistant LandauZener sweeps from geometrical curves Fei Zhuang, Junkai Zeng, Edwin Barnes, Sophia E. Economou The decoherence of a qubit due to environmental noise is a longstanding problem in quantum information science. Recent work provided a new recipe for designing dynamically corrected gates analytically using a simple geometric formalism. By adapting that formalism, we demonstrate how to design noiseresistant LandauZener sweeps through an avoided crossing. In the case where the avoided crossing is created purely from noise, we demonstrate identity gates and phase gates that are robust against error up to second order. In the more general case where the avoided crossing exists in the absence of noise, we show that robust sweeping protocols are in onetoone correspondence with curves lying on a sphere that obey certain constraints. We show how to exploit this correspondence to systematically construct noiseresistant LandauZener sweeps for generic avoided crossings. 
Friday, March 6, 2020 9:24AM  9:36AM 
W38.00008: Highperformance nonlinear optimization module for quantum control Harry Slatyer, Per Liebermann, Michael Hush, André Carvalho, Harrison Ball, Stephen Gore, Michael Biercuk Precise manipulation of quantum systems via shaped control pulses has emerged as a key area of development for quantum physics and chemistry. In nearterm quantum computers, for example, substitution of primitive operations with optimized noiserobust controls can yield improved fidelities for single and multiqubit gates without hardware modifications. However, for all but the most basic of systems, identifying ideal control pulses via analytic approaches is intractable, motivating an approach based on numerical optimization. In this talk we introduce a custom GPUcompatible optimization toolkit purposebuilt for rapidly creating highfidelity, noiserobust quantum controls in highdimensional Hilbert spaces. We describe the design of the toolkit, provide examples of standard and custom workflows, and present benchmarking results that demonstrate the speedup enabled by the GPUcompatible graph architecture. 
Friday, March 6, 2020 9:36AM  10:12AM 
W38.00009: Implementation of a canonical phase measurement with quantum feedback Invited Speaker: Irfan Siddiqi

Friday, March 6, 2020 10:12AM  10:24AM 
W38.00010: Twoqubit Pauliframe randomization in a superconducting system Matthew Ware, Guilhem Ribeill, Luke Govia Coherent noise and nonMarkovianity are projected to be significant sources of nonideal behavior in large scale quantum computers. One approach to dealing with such noise sources is called Randomized Compiling where quantum circuits are permuted by the insertion of random gates whose effect is tracked and inverted at the end of the circuit on a shotbyshot basis. While this technique effectively removes coherent error and significantly reduces nonMarkovianity, it can be quite challenging to implement experimentally due to the large number of random circuits that need to be generated and data that needs to be post processed. To remove some of the experimental overhead, we have implemented control system firmware that randomizes quantum circuits onthefly using custom control electronics. Here we build on previous work accomplishing this in a single qubit system extending it to circuits with two qubit gates. 
Friday, March 6, 2020 10:24AM  10:36AM 
W38.00011: Deep Reinforcement Learning for Quantum Control: Learning to Optimally Navigate in Complex Noisy Environments Gregory Quiroz, Paraj Titum, Kevin Schultz Quantum control seeks to establish control over a quantum system in such a way so that logical operations are implemented while simultaneously mitigating unwanted interactions between the system and its environment. From the point of view of quantum computation, quantum control can potentially provide significant improvements in computational accuracy when quantum logic operations are tailored for the particular noise plaguing the hardware. Specifically tailoring each controlled operation can be quite demanding if one wishes to perform this task for every instantiation of a quantum algorithm. Here, we examine how one can leverage reinforcement learning to learn and predict quantum gates in the presence of temporally correlated noise. We discuss how this information provides knowledge about optimal gate construction for noisetailored quantum algorithms, as well as how this approach potentially informs noise characterization. 
Friday, March 6, 2020 10:36AM  10:48AM 
W38.00012: Assigning Hamiltonians to Open Quantum Systems Eugen Dumitrescu, Pavel Lougovski

Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit 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 207403844
(301) 2093200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700