More on OTOCs and Chaos in Quantum Mechanics -- Magnetic Fields

• URL: http://arxiv.org/abs/2602.05322v1
• Date: Thu, 05 Feb 2026 05:42:20 GMT
• Title: More on OTOCs and Chaos in Quantum Mechanics -- Magnetic Fields
• Authors: Cameron Beetar, Jeff Murugan,
• Abstract summary: We revisit thermal out-of-time-order correlators (OTOCs) in single-particle quantum systems.<n>We compute the thermal OTOC $C_T(t) = -langle [x(t), p]2 rangle_$ and extract Lyapunov-like exponents $_L$ that quantify early-time growth.<n>In parallel, we compute an alternative OTOC built from guiding-center operators, which exhibits qualitatively distinct dynamics and no exponential growth.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We revisit thermal out-of-time-order correlators (OTOCs) in single-particle quantum systems, focusing on magnetic billiards. Using the stadium billiard as a testbed, we compute the thermal OTOC $C_T(t) = -\langle [x(t), p]^2 \rangle_β$ and extract Lyapunov-like exponents $λ_L$ that quantify early-time growth. We map out $λ_L(T, B)$, revealing a crossover from quantum chaos to magnetic rigidity. In parallel, we compute an alternative OTOC built from guiding-center operators, which exhibits qualitatively distinct dynamics and no exponential growth. Our results offer a controlled framework for probing scrambling, temperature dependence, and the interplay of geometry and magnetic fields in quantum systems.

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