Bulletin of the American Physical Society
53rd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 67, Number 7
Monday–Friday, May 30–June 3 2022; Orlando, Florida
Session E06: Progress Towards HighFidelity Quantum GatesRecordings Available

Hide Abstracts 
Chair: Bichen Zhang, Princeton University Room: Salon 1/2 
Tuesday, May 31, 2022 2:30PM  2:42PM 
E06.00001: Programmable Nbody interactions with trapped ion qubits Or Katz, Lei Feng, Andrew Risinger, Christopher Monroe, Marko Cetina The qubit and gate model of a quantum computer employs a universal set of operations, such as singlequbit rotations and twoqubit controlledNOT gates. While such fewqubit interactions are sufficient for general computation, and can be used to construct manybody entangled states, manyqubit interactions can dramatically simplify quantum circuit structures, speed up their execution, and extend the power of quantum computer systems facing decoherence. We describe a simple protocol for the singlestep generation of Nbody entangling interactions between trapped atomic ion qubits. We show that qubit statedependent squeezing operations and displacement forces on the collective atomic motion can generate full Nbody interactions. We show how this Nbody gate operation allows the singlestep implementation of a family of Nbit gate operations such as the powerful NToffoli gate, which flips a single qubit if and only if all other N1 qubits are in a particular state. 
Tuesday, May 31, 2022 2:42PM  2:54PM 
E06.00002: Towards standingwave MølmerSørensen gates on a quadrupole transition Oana Bazavan, Sebastian Saner, Mariella Minder, Amy Hughes, Raghavendra Srinivas, David M Lucas, Chris J Ballance

Tuesday, May 31, 2022 2:54PM  3:06PM 
E06.00003: Demonstration of nearinfrared light shift gate on optical qubits and investigation of laser noise impact on gate fidelity Nicole S Greene, Elia Perego The typical native entangling gate for trapped ion systems is the Mølmer Sørensen gate. Here we demonstrate a wavelength insensitive alternative, the light shift gate, on a pair of Ca 40 ions. Instead of driving red and blue tones, we construct a running lattice to impart a time varying state dependent force on the ion pair. This gate has many advantages such as a better interaction strength scaling with power (linear with power instead of electric field), wavelength insensitivity allowing us to work with IR light, which is more ideal for integrated optics applications, and because it is a σz⊗σz interaction, spin echo pulses commute with the gate eliminating σz errors from unwanted stark shifts or drifts in laser frequency. We are working with an optical qubit (729nm transition) and using 845nm light to drive the gate. Because we are driving the gate near a dipole transition and we specifically accumulate phase on the D state making for simpler gate dynamics. We study how it performs under various parameters such as speed, ion spacing, and motional heating. Additionally, we investigate how laser noise reduces fidelity. We attempt to quantify what range constitute "medium" noise which is too slow to be averaged out, but too fast relative to the gate time to act as a constant offset. 
Tuesday, May 31, 2022 3:06PM  3:18PM 
E06.00004: A laserdriven σ_{z}σ_{z} gate using a bichromatic quadrupole field Sebastian Saner, Oana Bazavan, Raghavendra Srinivas, Mariella Minder, Amy Hughes, David M Lucas, Chris J Ballance Twoqubit entangling gates are essential for quantum computing. We demonstrate a promising approach combining the advantages of two wellknown laserbased trappedion gate mechanisms, the lightshift gate and the Mølmer–Sørensen gate, which produce a σ_{z}σ_{z} and a σ_{φ}σ_{φ} interaction, respectively. Each scheme has unique advantages. The former acts on the computational basis and can therefore be combined with spinecho sequences to yield high resilience against a large class of gate errors, while the latter can be trivially implemented on clockqubits and the laser used to drive gates can be employed for singlequbit rotations as well. 
Tuesday, May 31, 2022 3:18PM  3:30PM 
E06.00005: Optical crosstalk mitigation methods for a trapped ion qubit array Roland Matt, Robin Oswald, Luca Huber, Jeremy B Flannery, Jonathan P Home We present experimental work performed in a cryogenic apparatus exploiting a segmented ion trap architecture for the implementation of quantum algorithms. The quantum register consists of a linear string of ^{40}Ca^{+} ions which are individually controlled by tightly focused laser beams perpendicular to the crystal axis. Light is delivered by a waveguide array allowing to individually feed each ion with a separately controlled laser beam. 
Tuesday, May 31, 2022 3:30PM  3:42PM 
E06.00006: Metastable Qubit Operations in ^{171}Yb^{+} Patrick J McMillin, Thomas Dellaert, Hassan Farhat, Conrad H Roman, Wesley C Campbell The metastable ("mtype") qubit defined on the zerofield hyperfine clock states in the longlived ^{2}F^{o}_{7/2} manifold in ^{171}Yb^{+} gives a promising pathway to low crosstalk, high fidelity multiqubit operations using the same ion species. We describe heralded state preparation, single qubit operations, and state measurement in the mtype qubit. Additionally, we put quantitative limits on the effect of direct illumination by ground state ("gtype") qubit state preparation and detection laser light on the mtype qubit coherence and operational frequency. We present our work toward coupling the mtype qubit to motion and coherent transfer between gtype and mtype qubits in ^{171}Yb^{+}. 
Tuesday, May 31, 2022 3:42PM  3:54PM 
E06.00007: Implementing RealTime Logical Qubit Error Detection & Correction on a Trapped Ion Quantum Computer Andrew Risinger, Alan Bell, Daniel Lobser, Crystal Noel, Bradley Bondurant, Laird Egan, Daiwei Zhu, Debopriyo Biswas, Or Katz, Marko Cetina, Christopher R Monroe Implementing a full errorcorrected logical qubit requires highfidelity gates, midcircuit ancilla measurement, and the determination of the appropriate correction operation using the measurement. Our recent results demonstrating the central components of quantum error correction [1] focused on a single cycle of error detection and correction, due to technical control limitations. Here, we discuss some of those limitations and present a heterogeneous approach to addressing this issue with a custom gate waveform generator. Finally, we will present progress towards demonstrating multiple rounds of error correction on a BaconShor13encoded logical qubit using trapped 171Yb+ ions. 
Tuesday, May 31, 2022 3:54PM  4:06PM Withdrawn 
E06.00008: Entanglinggate error from coherently displaced motional modes of trapped ions Brandon P Ruzic, Todd A Barrick, Jeffrey D Hunker, Ryan J Law, Brian K McFarland, Hayden J McGuinness, Lambert P Parazzoli, Jonathan D Sterk, Jay W Van Der Wall, Daniel L Stick Entangling gates in trappedion quantum computing have primarily targeted stationary ions with initial motional distributions that are thermal and close to the ground state. However, future systems will likely incur significant nonthermal excitation due to, e.g., ion transport, longer operational times, and increased spatial extent of the trap array. In this research, we analyze the impact of such coherent motional excitation on entanglinggate error by performing simulations of MølmerSørenson (MS) gates on a pair of trappedion qubits with both thermal and coherent excitation present in a shared motional mode at the start of the gate. We discover that a small amount of coherent displacement dramatically erodes gate performance in the presence of experimental noise, and we demonstrate that applying only limited control over the phase of the displacement can suppress this error. We then use experimental data from transported ions to analyze the impact of coherent displacement on MSgate error under realistic conditions. 
Tuesday, May 31, 2022 4:06PM  4:18PM Withdrawn 
E06.00009: One and twoqubit gate infidelities due to motional errors in trapped ions and electrons Robert T Sutherland, Qian Yu, Kristen M Beck, Hartmut Haeffner In this work, we derive analytic formulae that determine the effect of error mechanisms in laserfree one and twoqubit gates in trapped ions and electrons. First, we analyze, and derive expressions for, the effect of driving field inhomogeneities on onequbit gate fidelities. Second, we derive expressions for twoqubit gate errors, including static motional frequency shifts, trap anharmonicities, field inhomogeneities, heating, and motional dephasing. We show that, for small errors, each of our expressions for infidelity converges to its respective numerical simulation; this shows that our formulae are sufficient for determining error budgets for highfidelity gates, obviating numerical simulations in future projects. All of the derivations are general to any internal qubit state, and any \textit{mixed} state of the ion crystal's motion. Finally, we note that, while this manuscript focuses on laserfree systems, static motional frequency shifts, trap anharmonicities, heating, and motional dephasing are also important error mechanisms in laserbased gates, and our expressions apply. 
Tuesday, May 31, 2022 4:18PM  4:30PM 
E06.00010: Photon scattering rates in trapped ion qubits Isam D Moore, Wes Campbell, Eric R Hudson, Sean J Brudney, Andrew A Lesak, Jeremy M Metzner, Alexander D Quinn, David J Wineland, David T Allcock In trappedion qubits, gates are often performed using twophoton stimulated Raman transitions. During such a transition, there is a risk of spontaneous photon scattering, which reduces the gate fidelity. Some past models of these scattering rates are suitable for moderate detunings but lose accuracy the further the laser is tuned from resonance. We present calculations of the scattering rates and show how including certain corrections changes the predictions of the model, in particular, lower scattering rates at large red detuning. Additionally, we discuss recent experimental work from our lab towards measuring the scattering rates in this fardetuned regime. 
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. 
© 2023 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