https://doi.org/10.1140/epjs/s11734-025-01929-w
Regular Article
Amplitude mode at the superfluid-insulator transition on a random lattice
1
Department of Physics, Indian Institute of Technology Madras, 600036, Chennai, India
2
Center for Quantum Information, Communication and Computation (CQuICC), Indian Institute of Technology Madras, 600036, Chennai, India
3
Department of Physics, Missouri University of Science and Technology, 65409, Rolla, MO, USA
Received:
30
March
2025
Accepted:
5
September
2025
Published online:
15
September
2025
We study the superfluid-insulator quantum phase transition of interacting bosons by means of large-scale Monte Carlo simulations in the presence of both topological and generic quenched disorders. Recent work has demonstrated that the amplitude mode at this transition broadens and localizes in the presence of dilution disorder, whereas it remains a well-defined delocalized excitation for topological (connectivity) disorder. Here, we analyze the crossover between systems with purely topological disorder and systems with additional bond randomness to disentangle the roles that disorder and interactions play for amplitude mode localization. Specifically, we analyze the scalar susceptibility and its spectral density on both sides of the quantum phase transition. We also discuss the implications of our results for the potential observation of amplitude mode localization in experiments.
© The Author(s) 2025
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