The Sherwin lab is building a new magnetic resonance facility around a 16 Tesla magnet (for perspective, less than 1 Tesla is enough to lift a car!). We will primarily use the lab for Electron Paramagnetic Resonance (EPR) experiments, which is similar to its lower energy cousin, Nuclear Magnetic Resonance. EPR measures the energies and lifetimes of excited states constructed from electron spin. By taking advantage of UCSB’s Free Electron Laser, the new facility will be able to reach high frequencies (170 - 450 GHz) at high intensities (~kW of power) at high magnetic field strengths, making it a one-of-a-kind machine. These specs will allow the Sherwin lab to measure excitations with incredibly low lifetimes, on the order of a few nanoseconds. Many of the excitations in natively entangled materials, like those the Quantum Foundry studies, live within this timescale.
As a part of this long term project, every aspect of the lab has to be designed and developed. With the help of our collaborators in industry, we have been designing, building, and testing a new cold probe. The cold probe is used to place samples directly at the heart of the large magnet. Recently, we finished the design and troubleshooting of a new flange that makes exchanging sample holders faster and easier. The designs were made to be backwards compatible with previous sample holders. Additionally, some sample holders were rebuilt after many years of use.
The new flange and sample holders are now being used in experiments measuring Cu (L-met)_2. This copper compound is a crystallized amino acid. Due to the large organic structure within each unit cell, there is an incredibly weak antiferromagnetic exchange along 1D chains. Within the paramagnetic state, our collaborators at CEITEC Brno University of Technology observed evidence of a Quantum phase transition and emergent, many-body excited states within the material. Over the past few weeks, we have been attempting to measure the lifetime of these excitations to see if they’re consistent with long range entanglement.
Danieli, E. P., Álvarez, G. A., Levstein, P. R., & Pastawski, H. M. (2007). Quantum dynamical phase transition in a system with many-body interactions. Solid State Communications, 141(7), 422–426. doi:10.1016/j.ssc.2006.11.001
Álvarez, G. A., Danieli, E. P., Levstein, P. R., & Pastawski, H. M. (2006). Environmentally induced quantum dynamical phase transition in the spin swapping operation. The Journal of Chemical Physics, 124(19), 194507. doi:10.1063/1.2193518
Pastawski, H. M. (2007). Revisiting the Fermi Golden Rule: Quantum dynamical phase transition as a paradigm shift. Physica B: Condensed Matter, 398(2), 278–286. doi:10.1016/j.physb.2007.05.024
Eleuch, H., & Rotter, I. (2015). Nearby states in non-Hermitian quantum systems I: Two states. The European Physical Journal D, 69(10), 229. doi:10.1140/epjd/e2015-60389-7
Ashida, Y., Gong, Z., & Ueda, M. (2020). Non-Hermitian physics. Advances in Physics, 69(3), 249–435. doi:10.1080/00018732.2021.1876991
Levstein, P. R., Steren, C. A., Gennaro, A. M., & Calvo, R. (1988). EPR of layered magnetic metal-amino acid salts. II. Cu(L-Met)2. Chemical Physics, 120(3), 449–459. doi:10.1016/0301-0104(88)87231-8
Stoll, S., & Schweiger, A. (2006). EasySpin, a comprehensive software package for spectral simulation and analysis in EPR. Journal of Magnetic Resonance, 178(1), 42–55. doi:10.1016/j.jmr.2005.08.013
Anderson, P. W. (1954). A Mathematical Model for the Narrowing of Spectral Lines by Exchange or Motion. Journal of the Physical Society of Japan, 9(3), 316–339. doi:10.1143/JPSJ.9.316
