Quantum information scrambling in molecules

Zhang, Chenghao; Wolynes, Peter G.; Gruebele, Martin

doi:10.1103/physreva.105.033322

Cited by 9 publications

(3 citation statements)

References 77 publications

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“…Such “hyperfine” coupling can lead to spontaneous symmetry breaking in a finite system ( 31 , 64 ). These insights could prove useful for exploiting the exotic orientation state space of C 60 for quantum information processing ( 65 ) and for investigating the quantum-to-classical transition of information spreading ( 66 ). Ultimately, spectroscopy of C 60 isotopologs at ever-higher spectral resolution promises to uncover deeper insights into the emergent dynamics of mesoscopic quantum many-body systems.…”

Section: Discussionmentioning

confidence: 99%

Ergodicity breaking in rapidly rotating C ₆₀ fullerenes

Liu,

Rosenberg,

Changala

et al. 2023

Science

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Ergodicity, the central tenet of statistical mechanics, requires an isolated system to explore all available phase space constrained by energy and symmetry. Mechanisms for violating ergodicity are of interest for probing nonequilibrium matter and protecting quantum coherence in complex systems. Polyatomic molecules have long served as a platform for probing ergodicity breaking in vibrational energy transport. Here, we report the observation of rotational ergodicity breaking in an unprecedentedly large molecule, 12 C 60 , determined from its icosahedral rovibrational fine structure. The ergodicity breaking occurs well below the vibrational ergodicity threshold and exhibits multiple transitions between ergodic and nonergodic regimes with increasing angular momentum. These peculiar dynamics result from the molecule’s distinctive combination of symmetry, size, and rigidity, highlighting its relevance to emergent phenomena in mesoscopic quantum systems.

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Section: Discussionmentioning

confidence: 99%

Ergodicity breaking in rapidly rotating C ₆₀ fullerenes

Liu,

Rosenberg,

Changala

et al. 2023

Science

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“…Eq. 3 has been verified for a wide variety of model systems, ranging from few-dimensional models ( 15 – 17 ), to many-body fermionic systems, some of which, such as the Sachdev-Ye-Kitaev model ( 18 , 19 ), have been shown to saturate the bound. To our knowledge, no unifying mechanism has been proposed to explain how the bound is imposed in such a diverse range of systems, nor why it takes such a simple, system-independent form.…”

mentioning

confidence: 94%

Instantons and the quantum bound to chaos

Sadhasivam,

Meuser,

Reichman

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

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The rate at which information scrambles in a quantum system can be quantified using out-of-time-ordered correlators. A remarkable prediction is that the associated Lyapunov exponent λ that quantifies the scrambling rate in chaotic systems obeys a universal bound λ < 2 π k B T / ħ . Previous numerical and analytical studies have indicated that this bound has a quantum-statistical origin. Here, we use path-integral techniques to show that a minimal theory to reproduce this bound involves adding contributions from quantum thermal fluctuations (describing quantum tunneling and zero-point energy) to classical dynamics. By propagating a model quantum-Boltzmann-conserving classical dynamics for a system with a barrier, we show that the bound is controlled by the stability of thermal fluctuations around the barrier instanton (a delocalized structure which dominates the tunneling statistics). This stability requirement appears to be general, implying that there is a close relation between the formation of instantons, or related delocalized structures, and the imposition of the quantum-chaos bound.

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“…Quantum scrambling can play as big a role in molecular spectroscopy and solid-state materials ( 9 , 10 ) as it does in particle physics. Indeed we and collaborators have shown that vibrational energy hopping around in small molecules through Fermi resonances also allows quantum dynamics to get very close to the Maldacena bound ( 10 ). For small molecular models, it was possible to compute the OTOCs by exact quantum dynamics ( Fig.…”

mentioning

confidence: 99%

Quantum scrambling across an energy barrier

Wolynes,

Gruebele

2023

Proc. Natl. Acad. Sci. U.S.A.

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Quantum information scrambling in molecules

Cited by 9 publications

References 77 publications

Ergodicity breaking in rapidly rotating C ₆₀ fullerenes

Ergodicity breaking in rapidly rotating C ₆₀ fullerenes

Instantons and the quantum bound to chaos

Quantum scrambling across an energy barrier

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Quantum information scrambling in molecules

Cited by 9 publications

References 77 publications

Ergodicity breaking in rapidly rotating C 60 fullerenes

Ergodicity breaking in rapidly rotating C 60 fullerenes

Instantons and the quantum bound to chaos

Quantum scrambling across an energy barrier

Contact Info

Product

Resources

About

Ergodicity breaking in rapidly rotating C ₆₀ fullerenes

Ergodicity breaking in rapidly rotating C ₆₀ fullerenes