Event Date
We will be having Quantum Day @ UC Davis, from 9AM to 1PM at Kemper 1131. (Lunch will be provided at noon.) If you will be coming, please register using this link. To get the accurate headcount, please try to register ASAP.
Quantum Day: Schedule
9:00AM - 9:30AM: Pranta Saha
Title: Scalable Quantum Nanophotonics with Integrated Color Centers in Silicon Carbide
Abstract: We develop a wafer-scale process for quantum nanophotonics in silicon carbide (SiC), targeting scalable integration of color centers with photonic circuitry. Color centers in silicon carbide (SiC) are a promising platform for quantum information hardware, owing to their long spin coherence times and the ability to optically read out and entangle their spin states with NIR photons [1]. To fully leverage their capabilities, integration with photonic devices is essential for enhancing optical performance and scalability. Angle-etching has emerged as a prospective method for preserving color center quality enabling suspended photonic structures with a triangular cross-section. Notably, chip-scale experiments have demonstrated well-preserved optical and spin coherence of SiC color centers integrated with triangular waveguides [2]. In this work, we introduce a distinct approach by realizing wafer-scale angle-etching on an arbitrary SiC substrate in a Reactive Ion Beam Etching system [3]. Our simulation results demonstrate that the triangular geometry in SiC supports single-mode waveguide propagation [4], high-Q optical resonances [4], photonic band gap engineering [5], scalable mesh photonics [6], and efficient integration with on-chip SNSPDs [7]. To complete the photonic interface, fishbone grating couplers designed for this geometry offer efficient free-space coupling of color center emission, enabling scalable readout and on-chip connectivity [8]. [1] S. Majety, et al J. Appl. Phys. 131, 130901 (2022)
[2] C. Babin, et al Nat. Mater. 21, 67-73 (2022)
[3] S. Majety, et al npj Nanophoton. 2, 3 (2025)
[4] S. Majety et al J. Phys. Photonics 3 034008 (2021)
[5] P. Saha, et al Sci. Rep. 13, 4112 (2023)
[6] S. Majety, et al MRS Communications 14, 1262–1268 (2024)
[7] S. Majety, et al Mater. Quantum. Technol. 3 015004 (2023)
[8] P. Saha et al APL Mater. 13, 071102 (2025)
9:30AM - 10:00AM: Nate Gonzalez
Title: Quantum simulation of lattice gauge theories in a cavity QED platform
Abstract: Gauge theories underpin both the Standard Model of particle physics and many condensed-matter phenomena [1–7], but classical simulations are suffer from exponential resource demands [8]. Quantum simulators offer a path to explore non-perturbative and out-of-equilibrium dynamics that are out of reach of classical methods [9]. I will present a practical scheme for an all-photonic analog quantum simulator of a (1+1)-dimensional U(1) lattice gauge theory based on semiconductor nanophotonics. Our approach takes advantage of coupled cavity QED described by the Jaynes–Cummings–Hubbard Hamiltonian. By exploiting the non-uniform energy spectrum of the Jaynes–Cummings model and tuning resonances across the array, I will describe our proposal to experimentally realize the discrete quantum-link version of a U(1) gauge theory. The proposal provides a realistic and scalable platform for studying real-time gauge-field dynamics beyond the reach of classical computation.
Citations:
[1] John B. Kogut. An introduction to lattice gauge theory and spin systems. Reviews of Modern Physics, 51(4):659–713, October 1979.
[2] Franz J. Wegner. Duality in generalized ising models and phase transitions without local order parameters. Journal of Mathematical Physics, 12(10):22592272, October 1971.
[3] J. B. Kogut. Three Lectures on Lattice Gauge Theory, page 275–343. Springer US, Boston, MA, 1978. [4] Kenneth G. Wilson. Quarks and Strings on a Lattice, page 69–142. Springer US, Boston, MA, 1977. [5] John B. Kogut. The lattice gauge theory approach to quantum chromodynamics. Reviews of Modern Physics, 55(3):775–836, 1983.
[6] Henrik Bruus and Karsten Flensberg. Many–Body Quantum Theory in Condensed Matter Physics: An Introduction. Oxford University PressOxford, 2004.
[7] Yi Zhou, Kazushi Kanoda, and Tai-Kai Ng. Quantum spin liquid states. Reviews of Modern Physics, 89(2):025003, April 2017.
[8] Gaopei Pan and Zi Yang Meng. Sign Problem in Quantum Monte Carlo Simulation, page 879–893. 2024. arXiv:2204.08777 [cond-mat].
[9] U.-J. Wiese. Ultracold quantum gases and lattice systems: quantum simulation of lattice gauge theories. Annalen der Physik, 525(10–11):777–796, 2013.
10:00AM - 10:15AM: Break
10:15AM - 10:30AM: Lightning intros
10:30AM - 11:00AM: Samyak Surti
Title: Efficient simulation of logical magic state preparation protocols by removing non-Cliffordness
Abstract: Developing space- and time-efficient logical magic state preparation protocols will likely be an essential step towards building a large-scale fault-tolerant quantum computer. However, understanding the performance of these protocols has been difficult because of the simulation cost; the complexity of existing methods scale exponentially with the number of non-Clifford gates, making large-scale simulation challenging. We introduce a scalable method for simulating these protocols under standard circuit-level noise. When applied to protocols based on code switching and magic state cultivation, our method yields time and space complexity polynomial in (i) the number of qubits and (ii) the stabilizer rank of the final state in the protocol. Because the stabilizer rank of the final state is O(1) in many practical protocols of interest, our method can simulate such protocols efficiently. We also provide a method applicable to stabilizer simulation tools that do not track the global phase. The complexity of the simulation for this method depends on a mixed-state magic monotone, called Pauli rank.
11:00AM - Noon: Greg Kuperberg
Title: The hidden subgroup problem for infinite groups
Noon-1PM: Lunch