SQuInT 2022 Program
Full Program | Thursday | Friday | Saturday | All Sessions | Posters | Talks
SESSION 8: Ion-trap quantum computing (Islands Ballroom)Chair: (Sara Mouradian (Washington)) | |
| 1:30 pm - 2:15 pm | Crystal Noel, Duke (invited) Efficient tests of quantumness implemented on a trapped-ion quantum computer | Abstract. A test of quantumness is a protocol where a classical user issues challenges to a quantum device to determine if it exhibits non-classical behavior, under certain cryptographic assumptions. Interactive challenges can be used for tests of quantumness. They require only classical communication and are efficiently verifiable. In this talk, I will show how we implement the first interactive protocol using a trapped ion quantum computer. I will also describe how we execute an efficient non-interactive test of quantumness by modifying the original protocol. Our results significantly exceed the bound for a classical device's success. |
| 2:15 pm - 2:45 pm | Omid Khosravani, Duke University Noise-resilient quantum control | Abstract. One of the main obstacles in scaling up quantum computers is the accumulated noise throughout the quantum circuit. Various error-mitigation and quantum error-correction techniques have been proposed to mitigate and correct the noise. However, these techniques often come with substantially resource requirements that are highly sensitive to the infidelity of quantum gates. However, quantum gates are afflicted by various sources of coherent and incoherent noise that are embedded in quantum control as well as the qubit imperfections and the qubit environment which limits quantum gate fidelities. Here we present a theoretical framework as well as experimental demonstration for quantum gates that are insensitive to well-defined sources of noise up to a specified order. We first show how the quantum control problem can be cast into an optimization problem and provide a path integral picture to justify the noise-resilience of our quantum control framework. We then demonstrate our protocol by generating frequency-amplitude-phase modulated pulses to obtain high-fidelity two-qubit gates in a chain of trapped-ions. We model various sources of noise in two-qubit gates with trapped-ions including correlated electric fields, trap potential irregularities, crosstalk, as well as fluctuations in laser amplitude, frequency and phase, and show how they are mitigated within our framework. We finally discuss how our framework can be readily applied to two-qubit gates with superconducting qubits. |
| 2:45 pm - 3:15 pm | Nicole Greene, University of California Berkeley Demonstration of near-infrared light shift gate on optical qubits and investigation of laser noise impact on gate fidelity | Abstract. 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 794nm 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. |
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SQuInT Chief Organizer
Akimasa Miyake, Associate Professor
amiyake@unm.edu
SQuInT Co-Organizer
Hartmut Haeffner, Associate Professor, UC Berkeley
hhaeffner@berkeley.edu
SQuInT Administrator
Dwight Zier
d29zier@unm.edu
505 277-1850
SQuInT Program Committee
Alberto Alonso, Postdoc, UC Berkeley
Philip Blocher, Postdoc, UNM
Neha Yadav, Postdoc, UC Berkeley
Cunlu Zhou, Postdoc, UNM
SQuInT Founder
Ivan Deutsch, Regents' Professor, CQuIC Director
ideutsch@unm.edu
