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Title: One-component order parameter in URu 2 Si 2 uncovered by resonant ultrasound spectroscopy and machine learning
The unusual correlated state that emerges in URu 2 Si 2 below T HO = 17.5 K is known as “hidden order” because even basic characteristics of the order parameter, such as its dimensionality (whether it has one component or two), are “hidden.” We use resonant ultrasound spectroscopy to measure the symmetry-resolved elastic anomalies across T HO . We observe no anomalies in the shear elastic moduli, providing strong thermodynamic evidence for a one-component order parameter. We develop a machine learning framework that reaches this conclusion directly from the raw data, even in a crystal that is too small for traditional resonant ultrasound. Our result rules out a broad class of theories of hidden order based on two-component order parameters, and constrains the nature of the fluctuations from which unconventional superconductivity emerges at lower temperature. Our machine learning framework is a powerful new tool for classifying the ubiquitous competing orders in correlated electron systems.  more » « less
Award ID(s):
1719875 1752784
PAR ID:
10146278
Author(s) / Creator(s):
; ; ; ; ; ; ; ;
Date Published:
Journal Name:
Science Advances
Volume:
6
Issue:
10
ISSN:
2375-2548
Page Range / eLocation ID:
eaaz4074
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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