Wisconsin Quantum Institute |
Events During the Week of September 14th through September 21st, 2025
Monday, September 15th, 2025
- No events scheduled
Tuesday, September 16th, 2025
- No events scheduled
Wednesday, September 17th, 2025
- Succinct Arguments for BatchQMA and Friends under 8 rounds
- Time: 2:30 pm - 3:30 pm
- Place: Rm. 3610, Morgridge Hall
- Speaker: Rishab Goyal, UW-Madison
- Abstract: We study the problem of minimizing round complexity in the context of succinct classical argument systems for quantum computation. All prior works either require at least 8 rounds of interaction between the quantum prover and classical verifier, or rely on the idealized quantum random oracle model (QROM). We design:
1. A 4-round public-coin (except for the first message) argument system for batchQMA languages. Under the post-quantum hardness of functional encryption and learn- ing with errors (LWE), we achieve optimal communication complex- ity (i.e., all messages sizes are independent of batch size). If we only rely on the post-quantum hardness of LWE, then we can make all messages except the verifier’s first message to be independent of the batch size.
2. A 6-round private-coin argument system for monotone policy batchQMA languages, under the post-quantum hardness of LWE. The communication complexity is independent of the batch size as well as the monotone circuit size.
Unlike all prior works, we do not rely on “state-preserving” succinct arguments of knowledge (AoKs) for NP for proving soundness. Our main technical contribution is a new approach to prove soundness without rewinding cheating provers. We bring the notion of straight-line partial extractability to argument systems for quantum computation.
Thursday, September 18th, 2025
- No events scheduled
Friday, September 19th, 2025
- Atomic Physics Seminar
- Spin-Squeezed Atomic Clock with Precision Beyond the Standard Quantum Limit at the 10⁻¹⁸ Level
- Spin-Squeezed Atomic Clock with Precision Beyond the Standard Quantum Limit at the 10⁻¹⁸ Level
- Time: 10:00 am - 11:00 am
- Place: 5280 Chamberlin
- Speaker: Joonseok Hur, University of Colorado Boulder
- Abstract: Optical atomic clocks (OACs), utilizing optical transitions in atoms as a timebase, have achieved unprecedented precision and accuracy in scientific measurement, offering new frontiers in metrology and fundamental physics.
The precision of state-of-the-art OACs has reached the standard quantum limit (SQL), the fundamental bound set by quantum projection noise in measurements on uncorrelated atoms. While increasing atom numbers can statistically suppress this noise, it also introduces unwanted atomic interactions that compromise clock accuracy. Engineered entanglement between atoms can overcome the SQL, and atomic clocks with spin-squeezed states have demonstrated improved precision with various platforms. However, quantum advantage in entanglement-enhanced clocks, surpassing the best precision of conventional OACs, has yet to be achieved.
In this talk, I will present our spin-squeezed optical lattice clock that achieves precision beyond the SQL at the 10⁻¹⁸ level, representing a significant step toward quantum advantage in optical clocks. We squeezed the collective projection noise of 30,000 atoms by 7.1(1.0) dB using quantum nondemolition measurements mediated by strong atom-cavity coupling. Improved motional control preserves clock-state coherence, resulting in a 5.1(1.0) dB metrological enhancement. A synchronous comparison between two independent spin-squeezed clock ensembles demonstrates a 2.0(2) dB improvement beyond the SQL, reaching a fractional instability of 1.1×10⁻¹⁸.
This work marks a milestone toward quantum-enhanced timekeeping and provides a promising platform to explore the interplay between gravity and quantum entanglement. - Host: Josiah Sinclair