Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session C29: Superconducting Circuits: New Qubit Technologies and Design II 
Hide Abstracts 
Sponsoring Units: DQI Chair: Chen Wang, University of Massachusetts Amherst Room: BCEC 162A 
Monday, March 4, 2019 2:30PM  2:42PM 
C29.00001: Emergence of quasicharge in an ultrahighimpedance superconducting circuit: Design Ray Mencia, Ivan Pechenezhskiy, Long Nguyen, Vladimir Manucharyan We introduce an ultrahighimpedance superconducting circuit where the role of phase difference across a Josephson junction is replaced by quasicharge. This Hamiltonian is dual to that of the transmon, in which the kinetic energy term associated with the charging energy is replaced by the inductive energy. Our circuit consists of a smallarea Josephson junction shunted by a large linear inductance exceeding one microHenry. In such a circuit, the sensitivity of the ground to the first excited state transition is virtually flux insensitive while the fluxtunability of the transitions to higher excited states is largely preserved. Proper circuit design and choice of the fabrication techniques enable the mitigation of the parasitic capacitance previously associated with such large shunting inductances. In this talk, we demonstrate how the device spectra can be adequately described by the dual Hamiltonian and show that the flux dispersion of the qubit transition is reduced down to less than 100 MHz across the entire flux quantum. We also put a limit on the loss tangent of the inductor to be 5×10^{6}. 
Monday, March 4, 2019 2:42PM  2:54PM 
C29.00002: Emergence of quasicharge in an ultrahighimpedance superconducting circuit: Experiment Ivan Pechenezhskiy, Ray Mencia, Long Nguyen, Vladimir Manucharyan We introduce an ultrahighimpedance superconducting circuit where the role of phase difference across a Josephson junction is replaced by quasicharge. This Hamiltonian is dual to that of the transmon, in which the kinetic energy term associated with the charging energy is replaced by the inductive energy. Our circuit consists of a smallarea Josephson junction shunted by a large linear inductance exceeding one microHenry. In such a circuit, the sensitivity of the ground to the first excited state transition is virtually flux insensitive while the fluxtunability of the transitions to higher excited states is largely preserved. Proper circuit design and choice of the fabrication techniques enable the mitigation of the parasitic capacitance previously associated with such large shunting inductances. In this talk, we demonstrate how the device spectra can be adequately described by the dual Hamiltonian and show that the flux dispersion of the qubit transition is reduced down to less than 100 MHz across the entire flux quantum. We also put a limit on the loss tangent of the inductor to be 5×10^{6}. 
Monday, March 4, 2019 2:54PM  3:06PM 
C29.00003: Building Hamiltonians with Josephson PhaseSlip Qubits David Clarke, David Ferguson, Ryan J Epstein Tunable Josephson phaseslip qubits (JPSQs) present the possibility of constructing effective spin1/2 Hamiltonians with arbitrary 2local interactions using superconducting technology. Here, we discuss how this mapping is made, presenting a Paulioperator breakdown of the current and voltage dipoles of a JPSQ along a qubit annealing path that allows for preparation and readout in addition to the engineered couplings. As an example of the possibilities inherent in these devices, we present a system of JPSQs that adiabatically encodes or decodes a logical qubit in a [[4,1,2]] BaconShor code. 
Monday, March 4, 2019 3:06PM  3:18PM 
C29.00004: Characterization of Josephson phaseslip qubits, part 1: device fundamentals Cyrus F. Hirjibehedin, Steven J. Weber, Gabriel O. Samach, David K Kim, Alexander Melville, Bethany M. Niedzielski, Danna Rosenberg, Jonilyn L Yoder, William D Oliver, Andrew James Kerman The Josephson phaseslip qubit (JPSQ) [1] is a superconducting circuit that emulates a vector quantum S=1/2 system, with an effective dipole moment nearly independent of applied field, even near zero. This makes JPSQs ideal for emulating vector spin interactions, such as nonStoquastic +XX of interest for quantum annealing. We describe the design and operation of a JPSQ implementation. Using dispersive readout, we demonstrate the predicted periodic tuning with both flux and charge, and measure lifetimes in the microsecond regime. We also characterize the influence of charge jumps on the circuit’s operation. These results confirm the operating principles of the JPSQ and suggest that it could play an important role in a variety of quantum device architectures. 
Monday, March 4, 2019 3:18PM  3:30PM 
C29.00005: Characterization of Josephson phaseslip qubits, Part 2: Annealing Robert Hinkey, Moe Khalil, Sergey Novikov, David Clarke, James I. Basham, Steven Disseler, Alexander Marakov, Jeffrey Grover, David K Kim, Zachary A Stegen, Alexander Melville, Bethany M. Niedzielski, Jonilyn Yoder, Daniel A Lidar, Kenneth M. Zick, David Ferguson Josephson phase slip qubits (JPSQs) have been identified as a promising qubit with which to build nextgeneration quantum annealers. These qubits have charge tunability through the AharanovCasher effect. This charge tuning is a signature of their ability to achieve “strong” nonstoquastic XX couplings with “strong” indicating couplings that are large relative to residual single qubit fields. This coupling regime is not known to be possible to achieve with conventional flux qubits. In this talk we present initial characterization measurements of JPSQs that are annealingcompatible and have a large charge dispersion. 
Monday, March 4, 2019 3:30PM  3:42PM 
C29.00006: Classically reversible logic gate coupled to a superconducting qubit: Problem definition (pt. 1) Kevin Daniel Osborn, Waltraut Wustmann

Monday, March 4, 2019 3:42PM  3:54PM 
C29.00007: Classically reversible logic gate coupled to a superconducting qubit: Qubit simulation (pt. 2) Waltraut Wustmann, Kevin Daniel Osborn We theoretically study a classically reversible logic gate coupled to a superconducting qubit for potential applications in quantum computing. The classical gate consists of a Josephson junction circuit interface between long Josephson junctions, and the input of the gate is a ballistically traveling fluxon (a topological sineGordon soliton). Depending on the gate definition, a fluxon can undergo different types of resonant elastic scattering, e.g., forward scattering as fluxon or antifluxon. Here we report on how the scattering outcome can depend on the state of a qubit that is embedded in the interface, thus potentially allowing the readout of the qubit from the fluxon dynamics. We specifically will show the effect for a fluxonium qubit galvanically coupled through a junction in the gate interface. This presents a large 4piphase difference seen by the qubit. Different fluxon scatterings are found in the classical dynamics of the coupled system for the fluxonium qubit states with macroscopically different phases. We will further use a quantized version of a quasiparticle model, originally developed for classical gates, and take into account few fluxonium levels. The newer analysis should allow us to predict state evolution of a qubit strongly coupled to a topological soliton. 
Monday, March 4, 2019 3:54PM  4:06PM 
C29.00008: Quantum information processing using 3D multimode circuit QED Srivatsan Chakram, Ravi Naik, Akash Dixit, Yao Lu, Alexander Anferov, Nelson Leung, Andrew Oriani, David Schuster Multimode superconducting microwave cavities provide a hardware efficient means of engineering a large, highcoherence Hilbert space suitable for quantum information processing. When coupled to a superconducting transmon circuit, they can be used to construct random access quantum processors in which logic gates can be performed between arbitrary pairs of cavity modes via sideband transitions with the transmon [1]. We present our progress toward realizing such a processor using a seamless rectangular 3D multimode cavity  the quantum flute, with a tailored mode dispersion and decay times around a millisecond for tens of cavity modes. To eliminate coherent errors arising from multimode state dependent Stark shifts of the transmon, we introduce an intermediate singlemode 'manipulate' cavity with a tunable coupling to the multimode cavity. 
Monday, March 4, 2019 4:06PM  4:18PM 
C29.00009: Towards Developing a Graphene Josepheson junction based qubit device Kyle McElroy, Jesse E Thompson, Brandon T Blue, Lafe Spietz, Jacob Epstein, Masa Ishigami, Joan A Hoffmann Construction of Josepheson weak links is an integral part of superconducting quantum devices. New junction structures have various potential applications as new qubits or sensors. We will discuss the preliminary development of a transmon with a graphene based Josepheson junction. The devices are fabricated using epitaxially grown graphene, transferred to a sapphire base with standard lithographic techniques used for junction and antenna layout. The junctions are designed to have 0.30.85 nA critical currents and antenna geometry for device resonances between 26 GHz and are imbedded in a high Q 3D cavity at 7.7 GHz. 
Monday, March 4, 2019 4:18PM  4:30PM 
C29.00010: Quantum coherent control of graphenebased transmon qubit Joel Wang, Daniel Rodan Legrain, Charlotte Boettcher, Landry Bretheau, Daniel Campbell, Bharath Kannan, David K Kim, Morten Kjærgaard, Philip Krantz, Gabriel O. Samach, Fei Yan, Jonilyn L Yoder, Kenji Watanabe, Takashi Taniguchi, Terry Philip Orlando, Simon Gustavsson, Pablo JarilloHerrero, William D Oliver Van der Waals (vdW) materials–a family of layered crystals with various functionalities, can be assembled in specific arrangements to create new electronic devices called vdW heterostructures. The extraordinary and versatile electronic properties of these heterostructures, in combination with their epitaxial precision, make vdWbased devices a promising alternative for constructing key elements of novel solidstate quantum computing platforms.We demonstrate quantum coherent control of a superconducting circuit incorporating graphenebased vdW heterostructures. We show that this device can be operated as a voltagetunable transmon qubit, whose spectrum reflects the electronic properties of massless Dirac fermions traveling ballistically. In addition to the potential for advancing extensible quantum computing technology, our results represent a new approach to studying vdW materials using microwave photons in coherent quantum circuits.(arXiv:1809.05215) 
Monday, March 4, 2019 4:30PM  4:42PM 
C29.00011: Resonator Cavities Compatible with Epitaxial InAsAl Heterostructures Joseph Yuan, Matthieu Dartiailh, William Andrew Mayer, Eric Song, Kaushini Wickramasinghe, Javad Shabani Epitaxial AlInAs structures are prime candidates for tunable superconducting qubits, the socalled 
Monday, March 4, 2019 4:42PM  4:54PM 
C29.00012: Superconducting gatemon qubits based on selectiveareagrown semiconductor materials Albert Hertel, Laurits Orheim Andersen, Natalie Pearson, Malcolm R Connolly, Valentina Zannier, Lucia Sorba, Liu Yu, Peter Krogstrup, Geoffrey C. Gardner, Michael Manfra, Karl D Petersson, Charles M Marcus Semiconductorsuperconductor hybrid gatemon qubits offer a promising path to large scale quantum processors. In contrast to conventional transmon qubits that are controlled using currents, gatemons allow complete control using only gate voltages [1], potentially alleviating challenges to scaling superconducting qubits [2]. Here, we present a novel approach to building gatemons utilizing selectiveareagrown InAs structures on an InP substrate [3,4]. This approach allows deterministic placement and straightforward fabrication of the gatemon qubits. We characterize the material and perform first proofofprinciple measurements to demonstrate coherent qubit oscillations. Further work is needed to understand the dominant loss mechanisms and improve coherence times. 
Monday, March 4, 2019 4:54PM  5:06PM 
C29.00013: Control of topological properties in the Kitaev chain by quantum microwave radiation Fabio MéndezCórdoba, Fernando GómezRuiz, Juan MendozaArenas, Ferney Rodriguez, Carlos Tejedor, Luis Quiroga We investigate observable signatures coming from the lightmatter coupling of a Kitaev chain embedded in a microwave cavity. 
Monday, March 4, 2019 5:06PM  5:18PM 
C29.00014: Ultra lowloss singlecrystalline material platform for highQ quantum devices Ilya Rodionov, Aleksandr Baburin, Ilya A. Ryzhikov, Aidar R. Gabidullin, Dmitriy O. Moskalev, Alina Dobronosova, Alexey Matanin Quantum technologies is a rapidly grown research area, which have the potential to lead the revolution in supercomputing, sensing, global communications and security. The leading quantum computing concepts of design like superconductive qubits, optical quantum computing devices, solidstate and hybrid quantum systems are based on traditional semiconductor technology platform. However, new materials and nanoscale structures fabrication techniques are needed to explore the underlying physics and fulfill the subsequent specifications. Losses in thin films, surface, structure and interfaces quality are coming into the fore. 
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. 
© 2020 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700