Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session Y38: Quantum Control IIFocus Recordings Available
|
Hide Abstracts |
Sponsoring Units: DQI Chair: Qian Xu, University of Chicago Room: McCormick Place W-195 |
Friday, March 18, 2022 8:00AM - 8:12AM |
Y38.00001: Superconducting two-qubit gates using tunable couplers and accelerated adiabatic evolution Fnu Setiawan, Peter Groszkowski, Aashish Clerk Adiabatic evolution can be harnessed to design quantum gates which are remarkably robust against a variety of imperfections and system uncertainties; they unfortunately require extremely long gate times. Recent works [1,2] show how to mitigate this shortcoming using a shortcuts-to-adiabaticity (STA) approach, which through appropriate pulse modification can substantially accelerate adiabatic single-qubit gates. The accelerated gates are not only fast but still inherit the resilience to control-pulse imperfections. In this talk, I will extend STA quantum gate ideas to design a robust geometric two-qubit gate which can be readily applied to a variety of superconducting qubits such as fluxonia or transmons. Our approach represents a new method for realizing gates in qubit systems where coupling is mediated by an auxiliary coupler qubit or bus mode, and provides unique advantages. Further, while our approach is connected to Stimulated Raman Adiabatic Passage (STIRAP) protocol, it is considerably simpler (and less experimentally demanding) than the standard STIRAP-based geometric gate of Ref. [3]. I will give a detailed theoretical study of the performance of our two-qubit gate in a superconducting circuit consisting of two fluxonium qubits that interact via a coupling bus circuit. |
Friday, March 18, 2022 8:12AM - 8:24AM |
Y38.00002: Local Symmetric Quantum Circuits: How, in the presence of symmetry, locality restricts realizable unitaries Iman Marvian According to an elementary result in quantum computing, any unitary transformation on a composite system can be generated using 2-local unitaries, i.e., those that act only on two subsystems. Besides its fundamental importance in quantum computing, this result can also be regarded as a statement about the dynamics of systems with local Hamiltonians: although locality puts various constraints on the short-term dynamics, it does not restrict the possible unitary evolutions that a composite system with a general local Hamiltonian can experience after a sufficiently long time. We ask if such universality remains valid in the presence of conservation laws and global symmetries. In particular, can k-local symmetric unitaries on a composite system generate all symmetric unitaries on that system? Surprisingly, it turns out that the answer is negative in the case of continuous symmetries, such as U(1) and SU(2): generic symmetric unitaries cannot be implemented, even approximately, using local symmetric unitaries. In the context of quantum thermodynamics, this means that generic energy-conserving unitary transformations on a composite system cannot be implemented by applying local energy-conserving unitary transformations on the components. We also show how this no-go theorem can be circumvented via catalysis: any globally energy-conserving unitary can be implemented using a sequence of 2-local energy-conserving unitaries, provided that one can use a single ancillary qubit (catalyst). |
Friday, March 18, 2022 8:24AM - 8:36AM |
Y38.00003: Invalidating the Robustness Conjecture for Geometric Quantum Gates Ralph Kenneth L Colmenar, Utkan Güngördü, Jason P Kestner Geometric quantum gates are conjectured to be more resilient than dynamical gates against certain types of error, which makes them ideal for robust quantum computing. However, there are conflicting claims within the literature about the validity of that robustness conjecture. Here we use dynamical invariant theory in conjunction with filter functions in order to analytically characterize the noise sensitivity of an arbitrary quantum gate. For any control Hamiltonian that produces a geometric gate, we find that under certain conditions one can construct another control Hamiltonian that produces an equivalent dynamical gate with identical noise sensitivity (as characterized by the filter function). Our result holds for a Hilbert space of arbitrary dimensions, but we illustrate our result by examining experimentally relevant single-qubit scenarios and providing explicit examples of equivalent geometric and dynamical gates. |
Friday, March 18, 2022 8:36AM - 9:12AM |
Y38.00004: Quantum Technologies need a Quantum Energy Initiative. Invited Speaker: Alexia Auffeves Quantum technologies are currently the object of high expectations from governments and private companies, as they hold the promise to shape safer and faster ways to exchange and treat information. However, despite its major potential impact for industry and society, the question of their energetic footprint has remained in a blind spot of current deployment strategies. In this talk, I argue that quantum technologies must urgently plan for the creation of a transverse and interdisciplinary quantum energy sector, connecting quantum thermodynamicians, computer scientists and engineers. Structuring this sector is the only path towards sustainable quantum technologies, help reducing the cost of classical information processing, and possibly bring out an energetic quantum advantage. |
Friday, March 18, 2022 9:12AM - 9:24AM |
Y38.00005: Doubly Geometric Quantum Control Wenzheng Dong, Fei Zhuang, Sophia E Economou, Edwin Barnes In holonomic quantum computation, quantum gates are performed using driving protocols that trace out closed loops on the Bloch sphere, making them robust to certain pulse errors. However, dephasing noise that is transverse to the drive, which is significant in many qubit platforms, lies outside the family of correctable errors. Here, we present a general procedure that combines two types of geometry—holonomy loops on the Bloch sphere and geometric space curves in three dimensions—to design gates that simultaneously suppress pulse errors and transverse noise errors. We demonstrate this doubly geometric control technique by designing explicit examples of single-qubit and two-qubit dynamically corrected holonomic gates. |
Friday, March 18, 2022 9:24AM - 9:36AM |
Y38.00006: Experimental measurements of the performance of dynamically corrected geometric quantum logic gates in solid-state spin qubits Gurudev Dutt, Raees A Khan, Pubudu G Wijesinghe, Ahmed O Omran, Paul Hilaire, Edwin Barnes, Sophia E Economou High-fidelity quantum control is an important primitive in quantum information processing machines. Carrying out accurate, high-fidelity gates in presence of dephasing noise usually requires complicated pulse shapes which have to be carefully controlled. In this work, we study smooth pulses that were suggested theoretically from a geometrical framework to be resistant to dephasing noise [1]. We implement a randomized benchmarking protocol [2] with electronic spin qubits associated with nitrogen-vacancy (NV) centers in diamond to measure the performance and gate fidelity of these geometrically inspired smooth pulses. |
Friday, March 18, 2022 9:36AM - 9:48AM |
Y38.00007: Demonstration of high-fidelity universal gates on a continuously noise-decoupled qubit Michael Senatore, Daniel L Campbell, Oleksiy Redko, Matthew LaHaye Spin-Locking noise-spectroscopy of quantum systems is a valuable tool in qubit environment characterization. Intriguingly, though, a spin-locked state is itself a continuously noise-decoupled qubit, albeit with a small self-energy. Such spin-locked qubits are insensitive to 1/f noise in the lab frame, and therefore show enhanced long-time frequency stability. The small self-energy, however, makes resonant Rabi driving unsuitable for high fidelity control. We present the implementation and characterization of universal single qubit gates performed on a spin-locked transmon using an alternative control approach. |
Friday, March 18, 2022 9:48AM - 10:00AM |
Y38.00008: Fast high-fidelity entangling gates for silicon quantum dot spin qubits from geometric space curves Ho Lun Tang, Fei Zhuang, Ada Warren, Kyle Connelly, Sophia E Economou, Edwin Barnes
|
Friday, March 18, 2022 10:00AM - 10:12AM Withdrawn |
Y38.00009: Investigating effects of increased connectivity on superconducting qubit gate speed limits Joel Howard, Meenakshi Singh, Zhexuan Gong, David Pappas, Alexander Lidiak, Tongyu Zhao, Junling Long, Mustafa Bal Fast two-qubit entangling gates are essential for quantum computers with finite coherence times. Due to the limit of interaction strength among qubits, there exists a theoretical speed limit for a given two-qubit entangling gate. This speed limit has been explicitly found only for a two-qubit system and under the assumption of negligible single qubit gate time. We demonstrate such a speed limit experimentally using optimal control on two superconducting transmon qubits with a fixed capacitive coupling. We then investigate the effect of additional couplings on the speed limit, both through introduction of an ancillary qubit as well as through utilization of higher transmon energy states. Finally, we discuss the generalization to many qubit systems where properly leveraging all available couplings can provide dramatic speedups, thus necessitating the co-design of quantum computers from both theorists and experimentalists for optimal gate performance. |
Friday, March 18, 2022 10:12AM - 10:24AM |
Y38.00010: Generalized dynamical decoupling sequences for improved electron-nuclear entangling gates in defect systems Evangelia Takou, Edwin Barnes, Sophia Economou We design electron-nuclear gates applicable to defects in diamond or silicon carbide for arbitrary electron spin systems. We go beyond the standard CPMG and UDD dynamical decoupling sequences by allowing arbitrary interpulse spacings and rotations on the electronic spin. We study the range of entangling gates we can generate and the effect of unwanted spins on the target evolution. We quantify the selectivity of our sequences via multipartite entanglement measures, which capture the complete dynamical evolution of the system. |
Friday, March 18, 2022 10:24AM - 10:36AM |
Y38.00011: Quantum State Engineering with a Mancala Game on a Real Quantum Board Onur Danaci, William N DJAKAM, Robert Colemean, Michaela Amoo, Brian T Kirby, Ryan T Glasser, Moussa N'Gom, Thomas A Searles Quantum games can serve as research tools to simulate physical phenomena with near-term intermediate-scale quantum computers. Here, we propose ManQala as a quantum version of the sowing game Mancala. In ManQala, seeds, pits, and sowing are replaced by bosons, bosonic modes, and two-site hopping as encountered in the Bose-Hubbard model. We implement the game using IBM Qiskit by representing bosonic modes truncated to d=4 dimensional Hilbert space. And, represent these modes using standard binary encoding of qubits to simulate unitary moves through Trotter decomposition of the time-evolution. We find ManQala breaks the unidirectional gameplay of Mancala and introduces Mott-insulator like stalemate configurations that can only be broken through the introduction of probabilistic measurements. Further, ManQala corresponds to a quantum state engineering strategy that emulates the winnability conditions of the solitaire Mancala game on a quantum board by minimizing the number of projective measurements in a fixed unitary evolution and measurements (FUMES) type strategy. This way it steers an initial state to a target state more deterministically. |
Friday, March 18, 2022 10:36AM - 10:48AM |
Y38.00012: Towards Optimal Charging of a Many-Body Quantum Battery Sai Vinjanampathy, Ajinkya Werulkar, Victor Mukherjee
|
Friday, March 18, 2022 10:48AM - 11:00AM |
Y38.00013: Universal modeling of electrostatic semiconductor quantum gates of any topology interfaced to Josephson junction quantum circuit Krzysztof D Pomorski
|
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