Bulletin of the American Physical Society
APS March Meeting 2021
Volume 66, Number 1
Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session F33: Quantum Characterization, Verification, and Validation IIFocus Live

Hide Abstracts 
Sponsoring Units: DQI Chair: Kevin Young, Sandia National Laboratories 
Tuesday, March 16, 2021 11:30AM  11:42AM Live 
F33.00001: Qutrit Randomized Benchmarking on a Transmon Quantum Processor Alexis Morvan, Vinay Ramasesh, Machiel S Blok, John Mark Kreikebaum, Kevin O'Brien, Larry Chen, Ravi K. Naik, Brad Mitchell, David Ivan Santiago, Irfan Siddiqi Qutrits present an alternative to qubits for implementing quantum computation by using three, rather than twolevel systems, and have proven useful to explore connections between highenergy physics and quantum information science. Leveraging this extra level can also be used to extend the reach of current quantum hardware. In this talk, we present a scheme to generalize Randomized Benchmarking (RB) protocols to qutrits, and we experimentally implement them on a 5transmon processor. More specifically, we measure the performance of our singlequtrit gate with RB and interleaved RB. We then use cycle benchmarking to assess the performance of our CSUM gate  the generalization of the CNOT for qutrits. 
Tuesday, March 16, 2021 11:42AM  11:54AM Live 
F33.00002: Using Grover's search algorithm to test stateoftheart quantum platforms Vasily Geyko, Alessandro R Castelli, Max Porter, Ilon Joseph, Yuan Shi, Frank R Graziani, Stephen Bernard Libby, Yaniv J Rosen, Jonathan L DuBois In the present work, Grover's search algorithm is used to study performance of stateoftheart quantum platforms, such as LLNL Quantum Design and Integration Testbed (QuDIT), Rigetti and IBMQ. The algorithm is suited for three and four level quantum systems, thus, it is implemented on 2 qubits on Rigetti and IBM platforms and on a single transmon on the LLNL QuDIT. The population of the desired state is measured for different number of Grover's iterations and the results are compared to the analytically derived solution. The performance of the algorithm depends on the number of the system states, the marked state of the Oracle and the number of iterations. The observed fidelity loss is noticeably less for the LLNL QuDIT, as a small number of specially designed control pulses is used instead of a large sequence of native gates. For better understanding of the nature of the coherent and decoherent processes causing the fidelity decay, the algorithm is decomposed to main blocks and all of them are tested individually. 
Tuesday, March 16, 2021 11:54AM  12:06PM Live 
F33.00003: Experimental robust selftesting of the state generated by a quantum network Iris Agresti, Beatrice Polacchi, Davide Poderini, Emanuele Polino, Alessia Suprano, Ivan Supic, Joseph Bowles, Gonzalo Carvacho, Daniel Cavalcanti, Fabio Sciarrino In this work, we deal with the verification that the state generated by a quantum network corresponds to the desired target, with no assumptions on the adopted experimental platform, i.e. deviceindependently. Such a task is known as selftesting and its experimental implementations have been limited so far, by the fact that the majority of the existing protocols have low noise tolerance. In our case, we develop selftesting methods to deal with real imperfect conditions and show their applications to two experimentally implemented quantum networks. 
Tuesday, March 16, 2021 12:06PM  12:18PM Live 
F33.00004: Measuring the Quality of Boson Samplers in the Sparse Regime Jelmer Renema, Hui Wang, Jian Qin, Xiang You, ChaoYang Lu, JianWei Pan As quantum computational power increases, the key challenge for each platform is to demonstrate the quantum computational advantage that a given quantum device has over a classical one (‘quantum supremacy’). An essential aspect of this problem is verifying a claimed quantum advantage. Since a nogo theorem [1] forbids sampleefficient, deviceindependent verification for most QA platforms, the way forward is to construct a reasonable error model of a device, and measure the parameters of that model. In this work, we accomplish this for boson sampling [2], where the task is to sample from the output distribution of photons in a large linear optical network in the number basis. 
Tuesday, March 16, 2021 12:18PM  12:30PM Live 
F33.00005: Truncated moment sequences and a solution to the channel separability problem Nadia Milazzo, Daniel Braun, Olivier Giraud Verifying that quantum devices work in a properly quantum way has become of high relevance since the availability of the first smallscale quantum processors; an important requirement for such devices is the ability to create entanglement. To understand how entanglement evolves under physical operations acting on quantum states, we consider the problem of separability of quantum channels via the Choi matrix representation. We explore three classes of separability across different cuts between systems and ancillae and we provide a solution based on the mapping of the coordinates of the Choi state (in a fixed basis) to a truncated moment sequence (tms) y. This results in a necessary and sufficient condition for a channel to be separable or entanglement breaking. The algorithm we provide gives definiteness in the answer to the channel separability problem using semidefinite programming. The computational complexity and the performance depend on the number of variables n in the tms and on the size of the matrices involved in the semidefinite program. We investigate separability of 2qubit and singlequtrit channels; in the latter case we can provide an answer in cases where more straightforward separability criteria based on positive but not completely positive maps fail. 
Tuesday, March 16, 2021 12:30PM  12:42PM Live 
F33.00006: Hamiltonian MetaLearning Przemyslaw Bienias, Alireza Seif, Mohammad Hafezi, Paraj Titum, Norbert M Linke, Jiehang Zhang Precise calibration of quantum devices is necessary for reliable quantum information processing. Full characterization and tuning a quantum system without making any assumption require resources that scale exponentially with the system size. Here, we assume a model for the noisy evolution of a quantum system, and by using a machine learning technique known as metalearning to train an optimizer that finds model parameters with less resources than other gradientbased optimization algorithms. The training of our algorithm is done efficiently on smaller systems. However, the learned optimizer is transferable to larger and different systems. 
Tuesday, March 16, 2021 12:42PM  1:18PM Live 
F33.00007: Tomography and characterization of harmonic oscillator systems Invited Speaker: Christa Flühmann

Tuesday, March 16, 2021 1:18PM  1:30PM Live 
F33.00008: Optimal state tomography by measuring the qubit of a qubitqutrit system Violeta Nikolaeva IvanovaRohling, Guido Burkard, Niklas Rohling Measuring only one qubit in a composite quantum system is described by projectors on halfdimensional subspaces of the full Hilbert space. Despite the limitation these measurements can be combined with unitary operations in order to perform full quantum state tomography (QST). Moreover, for a system of qubits, measurement operators can be arranged in a fashion optimal for QST, i.e. such that the corresponding subspaces are mutually unbiased [1]. 
Tuesday, March 16, 2021 1:30PM  1:42PM Live 
F33.00009: Hamiltonian Tomography via Quantum Quench Zhi Li, Liujun Zou, Timothy Hsieh We show that it is possible to uniquely reconstruct a generic manybody local Hamiltonian from a single pair of initial and final states related by time evolution with the Hamiltonian. We then propose a practical version of the protocol involving multiple pairs of such initial/final states. Using the eigenstate thermalization hypothesis, we provide bounds on the protocol's performance and stability against errors from measurements and in the ansatz of the Hamiltonian. The protocol is efficient (requiring experimental resources scaling polynomially with system size in general and constant with system size given translation symmetry) and thus enables analog and digital quantum simulators to verify implementation of a putative Hamiltonian. 
Tuesday, March 16, 2021 1:42PM  1:54PM Live 
F33.00010: FrameBased FilterFunction Formalism for Quantum Characterization and Control Teerawat Chalermpusitarak, Behnam Tonekaboni, Yuanlong Wang, Leigh M Norris, Lorenza Viola, Gerardo A Paz Silva A key obstacle to achieve optimal control performance is the interaction between the target system and its unknown environment. Thus, obtaining a quantitative characterization of such environment is instrumental. We introduce a new framework for resourceefficient characterization and control of nonMarkovian open quantum systems, which allows for the integration of given, experimentally motivated, control capabilities and constraints. This is achieved by developing a transfer filterfunction formalism based on the notion of a frame and by tying the choice of frame to the available control. While recovering the standard frequencybased filterfunction formalism as a special instance, this controladapted generalization affords intrinsic flexibility and allows us to overcome limitations of existing approaches. In particular, we show how to implement quantum noise spectroscopy in the presence of nonstationary noise sources, and how to achieve controldriven model reduction for noisetailored optimized quantum gate design. 
Tuesday, March 16, 2021 1:54PM  2:06PM Not Participating 
F33.00011: Framebased filterfunction formalism for quantum characterization and control  Part II. Noisetailored gate design Teerawat Chalermpusitarak, Behnam Tonekaboni, Yuanlong Wang, Leigh M Norris, Lorenza Viola, gerardo pazsilva Abstract: This is the second part of the work ``Framebased filterfunction formalism for quantum characterization and control". 
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