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JQI Seminar

Mon, Nov 29, 2021 11:00 am - 12:00 pm
ATL 2400


Speaker: Christopher Laumann

Institition: Boston University

Title: The fine structure of quantum spin ice

Abstract: Quantum spin liquids are low temperature phases of magnetic materials in which quantum fluctuations prevent the establishment of long-range magnetic order. These phases support fractionalized spin excitations (spinons) coupled to emergent photons. In this talk, I will review the basic picture of how quantum electrodynamics emerges in 3D spin ice and then turn to several results regarding its `fine structure'. I will argue that the fine structure constant 𝜶 -- the dimensionless coupling which controls the interactions between light and matter -- generically takes values ~0.1 in quantum spin ice, much larger than the 𝜶 ~ 1/137 of our universe [1]. The large fine structure constant modifies the spinon dynamics considerably. The consequent qualitative features in inelastic neutron scattering could help identify these phases [2]. Time permitting, I will also discuss how axions can appear in the system [3].

[1] Pace, Morampudi, Moessner, Laumann. Phys. Rev. Lett. 127, 117205 (2021).
[2] Morampudi, Wilczek, Laumann. Phys. Rev. Lett. 124, 097204 (2020).
[3] Pace, Castelnovo, Laumann. arXiv:2109.06890.

Host: Jay Sau