† Contributed equally to this project. Magnetic monopoles 1 -3 are hypothetical elementary particles exhibiting quantized magnetic charge = ±( ) ⁄ and quantized magnetic flux = ± / . In principle, such a magnetic charge can be detected by the quantized jump in magnetic flux it generates upon passage through a superconducting quantum interference device (SQUID) 4 . Naturally, with the theoretical discovery that a plasma of emergent magnetic charges should exist in several lanthanide-pyrochlore magnetic insulators 5,6 including Dy2Ti2O7, this SQUID technique was proposed for their direct detection 6 . Experimentally, this has proven challenging because of the high number density, and the generation-recombination (GR) fluctuations, of the monopole plasma. Recently, however, theoretical advances have allowed the spectral density of magnetic-flux noise ( , ) due to GR fluctuations of ± * magnetic charge pairs to be predicted 7 , 8 . Here we report development of a SQUID based flux-noise spectrometer, and consequent measurements of the frequency and temperature dependence of ( , ) for Dy2Ti2O7 samples. Virtually all the elements of ( , )predicted for a magnetic monopole plasma, including the existence of intense magnetization noise and its characteristic frequency and temperature dependence,
The series "Springer Theses" brings together a selection of the very best Ph.D. theses from around the world and across the physical sciences. Nominated and endorsed by two recognized specialists, each published volume has been selected for its scientific excellence and the high impact of its contents for the pertinent field of research. For greater accessibility to non-specialists, the published versions include an extended introduction, as well as a foreword by the student's supervisor explaining the special relevance of the work for the field. As a whole, the series will provide a valuable resource both for newcomers to the research fields described, and for other scientists seeking detailed background information on special questions. Finally, it provides an accredited documentation of the valuable contributions made by today's younger generation of scientists.
Measurement has a special role in quantum theory 1 : by collapsing the wavefunction it can enable phenomena such as teleportation 2 and thereby alter the "arrow of time" that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time 3-10 that go beyond established paradigms for characterizing phases, either in or out of equilibrium [11][12][13] . On present-day NISQ processors 14 , the experimental realization of this physics is challenging due to noise, hardware limitations, and the stochastic nature of quantum measurement. Here we address each of these experimental challenges and investigate measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping 9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases-from entanglement scaling 3,4 to measurement-induced teleportation 18 -in a unified way. We obtain finite-size signatures of a phase transition with a decoding protocol that correlates the experimental measurement record with classical simulation data. The phases display sharply different sensitivity to noise, which we exploit to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realize measurement-induced physics at scales that are at the limits of current NISQ processors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.