Pseudo-Majorana functional renormalization for frustrated XXZ spin- 12 models with field or magnetization along the spin- Z direction at finite temperature

Physical review. B./Physical review. B, Journal Year: 2025, Volume and Issue: 111(5)

Published: Feb. 13, 2025

The numerical study of high-dimensional frustrated quantum magnets remains a challenging problem. Here we present an extension the pseudo-Majorana functional renormalization group to spin-1/2 XXZ-type Hamiltonians with field or magnetization along spin-Z direction at finite temperature. We consider U(1) symmetry-adapted fermionic spin representation and derive diagrammatic framework its flow equations. discuss benchmark results application two antiferromagnetic triangular lattice materials recently studied in experiments applied magnetic fields: First, numerically reproduce data measured for CeMgAl11O19 confirming model parameters previously estimated from inelastic neutron spectrum high fields. Second, showcase accuracy our method by studying thermal phase transition into solid up-up-down Na2BaCo(PO4)2 good agreement experiment. Published American Physical Society 2025

Language: Английский

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Magnetism in the two-dimensional dipolar XY model

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 109(14)

Published: April 12, 2024

Motivated by a recent experiment on square-lattice Rydberg atom array realizing long-range dipolar XY model [C. Chen et al., Nature (London) 616, 691 (2023)], we numerically study the model's equilibrium properties. We obtain phase diagram, critical properties, entropies, variance of magnetization, and site-resolved correlation functions. consider both ferromagnetic antiferromagnetic interactions apply quantum Monte Carlo pseudo-Majorana functional renormalization group techniques, generalizing latter to $U(1)$ symmetric setting. Our simulations perform extensive thermometry in arrays establish conditions for adiabaticity thermodynamic equilibrium. On side experiment, determine entropy per particle $S/N\ensuremath{\approx}0.5$, close one at temperature, ${S}_{c}/N=0.585(15)$. The suggest presence an out-of-equilibrium plateau large distances function, thus motivating future studies nonequilibrium dynamics system.

Language: Английский

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Taming Spin Susceptibilities in Frustrated Quantum Magnets: Mean-Field Form and Approximate Nature of the Quantum-to-Classical Correspondence

Physical Review Letters, Journal Year: 2025, Volume and Issue: 134(17)

Published: April 29, 2025

In frustrated magnetism, the empirically found quantum-to-classical correspondence (QCC) matches real-space static susceptibility pattern of a quantum spin-1/2 model with its classical counterpart computed at certain elevated temperature. This puzzling relation was observed via bold line diagrammatic Monte Carlo simulations in dimensions two and three. The matching within error bars seemed valid down to lowest accessible temperatures T about an order magnitude smaller than exchange coupling J. Here, we employ resummed spin perturbation theory show analytically that QCC breaks weakly fourth J/T provide approximate mapping between temperatures. Our treatment further reveals is indication surprising accuracy which correlators can be approximated by simple renormalized mean-field form. We illustrate this for all models discussed context so far, including recent example S=1 material K2Ni2(SO4)3. success form traced back partial cancellations. Published American Physical Society 2025

Language: Английский

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Competing gauge fields and entropically driven spin liquid to spin liquid transition in non-Kramers pyrochlores

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(36)

Published: Aug. 28, 2024

Gauge theories are powerful theoretical physics tools that allow complex phenomena to be reduced simple principles and used in both high-energy condensed matter physics. In the latter context, gauge becoming increasingly popular for capturing intricate spin correlations liquids, exotic states of which dynamics quantum spins never ceases, even at absolute zero temperature. We consider a system on three-dimensional pyrochlore lattice where emergent fields not only describe liquid behavior temperature but crucially determine system’s evolution, with distinct giving rise different phases separate regimes. Focusing first classical spins, an intermediate regime, shows unusual coexistence vector tensor former is known from ice systems while has been associated fractonic quasiparticles, peculiar type excitation restricted mobility. Upon cooling, transitions into low-temperature phase entropic selection mechanism depopulates degrees freedom field, rendering spin-ice-like. further provide numerical evidence corresponding model, coexisting finite window stability parameter space interactions down Finally, we discuss relevance our findings non-Kramers magnetic materials.

Language: Английский

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Phase diagram of the J−Jd Heisenberg model on the maple leaf lattice: Neural networks and density matrix renormalization group

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 109(18)

Published: May 10, 2024

We microscopically analyze the nearest-neighbor Heisenberg model on maple leaf lattice through neural quantum state (NQS) and infinite density matrix renormalization group (iDMRG) methods. Embarking to parameter regimes beyond exact dimer singlet ground with a bond spin exchange coupling ${J}_{d}$ varied against strength $J$ of all other bonds, iDMRG method finds paramagnetic phase for ${J}_{d}/J>1.464$ (${J}_{d}/J>1.39$) canted ${120}^{\ensuremath{\circ}}$ magnetic order ${J}_{d}/J<1.419$ (${J}_{d}/J<1.23$). Assessing training convergence inaccuracies NQS influence finite cylindric circumference in method, we discuss possible existence an intermediate between magnet paramagnet.

Language: Английский

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Dynamics of K2Ni2(SO4)3 governed by proximity to a 3D spin liquid model

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Aug. 21, 2024

Quantum spin liquids (QSLs) have become a key area of research in magnetism due to their remarkable properties, such as long-range entanglement, fractional excitations, and topologically protected phenomena. Recently, the search for QSLs has expanded into three-dimensional world, despite suppression quantum fluctuations high dimensionality. A new candidate material, K2Ni2(SO4)3, belongs langbeinite family consists two interconnected trillium lattices. Although magnetically ordered, it exhibits highly dynamical correlated state. In this work, we combine inelastic neutron scattering measurements with density functional theory (DFT), pseudo-fermion renormalization group (PFFRG), classical Monte Carlo (cMC) calculations study magnetic properties revealing level agreement between experiment theory. We further reveal origin state K2Ni2(SO4)3 be centred around network composed tetrahedra on lattice. liquid signatures been found 3D systems. Here, using combination calculations, authors dynamic identifying region theoretical phase diagram.

Language: Английский

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Temperature flow in pseudo-Majorana functional renormalization for quantum spins

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 109(19)

Published: May 3, 2024

We implement the temperature flow scheme first proposed by Honerkamp and Salmhofer [Phys. Rev. B 64, 184516 (2001)] into pseudo-Majorana functional renormalization group method for quantum spin systems. Since parameter in this approach is a physical quantity, $T$, numerical efficiency increases significantly compared to more conventional parameters, especially when computing finite-temperature phase diagrams. apply determine diagram of ${J}_{1}\text{\ensuremath{-}}{J}_{2}$ Heisenberg model on simple cubic lattice, where our findings support claims vanishingly small nonmagnetic around high frustration point ${J}_{2}=0.25{J}_{1}$. Perhaps most importantly, we find be advantageous detecting transitions as, construction, transition never encountered at an artificial, unphysical cutoff parameter. Finally, dipolar XXZ square rich with large regime down lowest accessible temperatures. Wherever comparison error-controlled (quantum) Monte Carlo methods applicable, excellent quantitative agreement less than $5%$ deviation from numerically exact results.

Language: Английский

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Pseudofermion functional renormalization group study of dipolar-octupolar pyrochlore magnets

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 109(18)

Published: May 10, 2024

Motivated by recent experiments on Ce2Zr2O7 that reveal a dynamic, liquidlike ground state, we study the nearest-neighbor XYZ Hamiltonian of dipolar-octupolar pyrochlore magnets with pseudofermion functional renormalization group (PFFRG), which is numerically implemented software. Taking interaction between octupolar components to be dominant and antiferromagnetic, map out phase diagram demarcating quantum disordered magnetically ordered states. We identify four distinct phases, namely, 0-flux π-flux spin ices all-in-all-out magnetic orders along local z x axes. further use static two-spin correlation output PFFRG algorithm compute polarized neutron scattering cross sections, are able capture several qualitative features observed experimentally, in materially relevant parameter regime stabilizes π-flux ice. Our results provide support for spin-liquid state Ce2Zr2O7. Published American Physical Society 2024

Language: Английский

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Noncoplanar orders and quantum disordered states in maple-leaf antiferromagnets

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 110(8)

Published: Aug. 27, 2024

A promising route towards the realization of chiral spin liquids is quantum melting classically noncoplanar states via fluctuations. In classical realm, such orders can effectively be stabilized by interactions beyond nearest neighbors. Motivated recent synthesis materials with a maple-leaf lattice geometry, we study effect cross-plaquette couplings on elementary Heisenberg antiferromagnets for this geometry (as well as their ferromagnetic counterparts). We find rich spectrum states, including an icosahedral order incommensurate spirals, using large-scale Monte Carlo simulations in combination semianalytical analysis. To inspect potential these analyze $S=1/2$ variant models pseudofermion functional renormalization group simulations. Notably, indeed extended parameter regimes lacking long-range magnetic order---in regions occupied orders---which putatively identify possible formation liquids.

Language: Английский

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Higher-rank spin liquids and spin nematics from competing orders in pyrochlore magnets

Physical review. B./Physical review. B, Journal Year: 2025, Volume and Issue: 111(8)

Published: Feb. 19, 2025

Language: Английский

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