Quantum Supercritical Regime with Universal Magnetocaloric Scaling in Ising Magnets

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Hauptverfasser: Lv, Enze, Xi, Ning, Jin, Yuliang, Li, Wei
Format: Preprint
Veröffentlicht: 2024
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author Lv, Enze
Xi, Ning
Jin, Yuliang
Li, Wei
author_facet Lv, Enze
Xi, Ning
Jin, Yuliang
Li, Wei
contents Quantum critical points ubiquitously emerge in strongly correlated systems, with their influence persisting at finite temperatures and external fields. A paradigmatic example is the quantum Ising magnet, where transverse field $g$ controlling quantum fluctuations can expand the quantum critical point into an extended quantum critical regime. In this work, we propose a distinct quantum supercritical regime originating also from the quantum critical point but controlled by the longitudinal field $h$ coupled to the order parameter. Through thermal tensor network simulations, we find the quantum supercritical regime is enclosed by the finite-temperature crossover boundaries $T \propto h^{{zν}/Δ}$, where $z$, $ν$ and $Δ\equiv β+γ$ are critical exponents. We comprehend the supercritical scaling via thermal data collapse based on the derived scaling form. Amongst other intriguing phenomena in quantum supercritical regime, there exists an enhanced magnetocaloric effect characterized by a universally diverging magnetic Grüneisen ratio $Γ_h \propto T^{-Δ/{zν}}$, which indicates that a small symmetry-breaking field $h$ can generate dramatic temperature variation. We propose to observe the quantum supercritical regime in Ising-chain compound CoNb$_2$O$_6$ and related quantum materials, revealing a helium-3-free pathway to millikelvin cooling via the supercritical magnetocaloric effect.
format Preprint
id arxiv_https___arxiv_org_abs_2410_22236
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum Supercritical Regime with Universal Magnetocaloric Scaling in Ising Magnets
Lv, Enze
Xi, Ning
Jin, Yuliang
Li, Wei
Strongly Correlated Electrons
Quantum critical points ubiquitously emerge in strongly correlated systems, with their influence persisting at finite temperatures and external fields. A paradigmatic example is the quantum Ising magnet, where transverse field $g$ controlling quantum fluctuations can expand the quantum critical point into an extended quantum critical regime. In this work, we propose a distinct quantum supercritical regime originating also from the quantum critical point but controlled by the longitudinal field $h$ coupled to the order parameter. Through thermal tensor network simulations, we find the quantum supercritical regime is enclosed by the finite-temperature crossover boundaries $T \propto h^{{zν}/Δ}$, where $z$, $ν$ and $Δ\equiv β+γ$ are critical exponents. We comprehend the supercritical scaling via thermal data collapse based on the derived scaling form. Amongst other intriguing phenomena in quantum supercritical regime, there exists an enhanced magnetocaloric effect characterized by a universally diverging magnetic Grüneisen ratio $Γ_h \propto T^{-Δ/{zν}}$, which indicates that a small symmetry-breaking field $h$ can generate dramatic temperature variation. We propose to observe the quantum supercritical regime in Ising-chain compound CoNb$_2$O$_6$ and related quantum materials, revealing a helium-3-free pathway to millikelvin cooling via the supercritical magnetocaloric effect.
title Quantum Supercritical Regime with Universal Magnetocaloric Scaling in Ising Magnets
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2410.22236