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Excitation Amplitude Sampling for Low Variance Electronic Structure on Quantum Computers
Connor Lenihan, Oliver J. Backhouse, Tom W. A. Montgomery, Phalgun Lolur, M. J. Bhaseen, George H. Booth
https://arxiv.org/abs/2506.15438

Excitation Amplitude Sampling for Low Variance Electronic Structure on Quantum Computers
We combine classical heuristics with partial shadow tomography to enable efficient protocols for extracting information from correlated ab initio electronic systems encoded on quantum devices. By proposing the use of a correlation energy functional and sampling of a polynomial set of excitation amplitudes of the quantum state, we can demonstrate an almost two order of magnitude reduction in required number of shots for a given statistical error in the energy estimate, as well as observing a lin…

Flux Trapping Characterization for Superconducting Electronics Using a Cryogenic Widefield NV-Diamond Microscope
Rohan T. Kapur, Pauli Kehayias, Sergey K. Tolpygo, Adam A. Libson, George Haldeman, Collin N. Muniz, Alex Wynn, Nathaniel J. O'Connor, Neel A. Parmar, Ryan Johnson, Andrew C. Maccabe, John Cummings, Justin L. Mallek, Danielle A. Braje, Jennifer M. Schloss

Flux Trapping Characterization for Superconducting Electronics Using a Cryogenic Widefield NV-Diamond Microscope
Magnetic flux trapping is a significant hurdle limiting reliability and scalability of superconducting electronics, yet tools for imaging flux vortices remain slow or insensitive. We present a cryogenic widefield NV-diamond magnetic microscope capable of rapid, micron-scale imaging of flux trapping in superconducting devices. Using this technique, we measure vortex expulsion fields in Nb thin films and patterned strips, revealing a crossover in expulsion behavior between $10$ and $20~μ$m strip…