Bilayer t−J−J⊥ Model and Magnetically Mediated Pairing in the Pressurized Nickelate La

Physical Review Letters, Journal Year: 2024, Volume and Issue: 132(3)

Published: Jan. 19, 2024

The recently discovered nickelate superconductor La_{3}Ni_{2}O_{7} has a high transition temperature near 80 K under pressure, providing an additional avenue for exploring unconventional superconductivity. Here, with state-of-the-art tensor-network methods, we study bilayer t-J-J_{⊥} model and find robust s-wave superconductive (SC) order mediated by interlayer magnetic couplings. Large-scale density matrix renormalization group calculations algebraic pairing correlations Luttinger parameter K_{SC}≲1. Infinite projected entangled-pair state method obtains nonzero SC directly in the thermodynamic limit, estimates strong strength Δ[over ¯]_{z}∼O(0.1). Tangent-space tensor simulations elucidate evolution of further determine T_{c}^{*}/J∼O(0.1). Because intriguing orbital selective behaviors Hund's rule coupling compound, spin exchange (while negligible hopping), which greatly enhances system. Such magnetically also been observed optical lattice ultracold atoms. Our accurate comprehensive reveal shed light on mechanism high-T_{c} superconductor.

Language: Английский

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Giant magnetocaloric effect in spin supersolid candidate Na2BaCo(PO4)2

Nature, Journal Year: 2024, Volume and Issue: 625(7994), P. 270 - 275

Published: Jan. 10, 2024

Language: Английский

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Orbital-selective superconductivity in the pressurized bilayer nickelate La3Ni2O7 : An infinite projected entangled-pair state study

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 110(4)

Published: July 8, 2024

The newly discovered high-${T}_{c}$ nickelate superconductor ${\mathrm{La}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{7}$ has generated significant research interest. To uncover the pairing mechanism, it is essential to investigate intriguing interplay between two ${e}_{g}$, i.e., ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ and ${d}_{{z}^{2}}$ orbitals. Here we conduct an infinite projected entangled-pair state (iPEPS) study of bilayer $t\text{\ensuremath{-}}J$ model, directly in thermodynamic limit with orbitally selective parameters for orbitals, respectively. electrons exhibit intralayer hopping ${t}_{\ensuremath{\parallel}}$ (and spin couplings ${J}_{\ensuremath{\parallel}}$) as well strong interlayer ${J}_{\ensuremath{\perp}}$ passed from electrons. However, ${t}_{\ensuremath{\perp}}$ negligible this case. In contrast, orbital demonstrates ${J}_{\ensuremath{\perp}}$, while inherent ${J}_{\ensuremath{\parallel}}$ are small. Based on iPEPS results, find clear orbital-selective behaviors ${\mathrm{La}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{7}$. orbitals robust superconductive (SC) order driven by coupling band shows relatively weak SC a result small (lack coherence) but large (strong Pauli blocking). Furthermore, substituting rare-earth element Pm or Sm La, enhanced order, which opens up promising avenue discovering superconductors even higher ${T}_{c}$.

Language: Английский

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Magnetic, thermodynamic, and dynamical properties of the three-dimensional fermionic Hubbard model: A comprehensive Monte Carlo study

Physical review. B./Physical review. B, Journal Year: 2025, Volume and Issue: 111(3)

Published: Jan. 10, 2025

Language: Английский

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Variational neural and tensor network approximations of thermal states

Physical review. B./Physical review. B, Journal Year: 2025, Volume and Issue: 111(7)

Published: Feb. 3, 2025

We introduce a variational Monte Carlo algorithm for approximating finite-temperature quantum many-body systems, based on the minimization of modified free energy. This approach directly approximates state at fixed temperature, allowing systematic improvement expressiveness without accumulating errors from iterative imaginary-time evolution. employ variety trial states—both tensor networks as well neural networks—as our numerical optimization. benchmark and compare different constructions in above classes, both one- two-dimensional problems, with systems made up to N=100 spins. Our results demonstrate that while restricted Boltzmann machines show limitations, string bond network states exhibit improvements increasing dimensions number strings. Published by American Physical Society 2025

Language: Английский

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Clifford Circuits Augmented Time-Dependent Variational Principle

Physical Review Letters, Journal Year: 2025, Volume and Issue: 134(15)

Published: April 15, 2025

The recently proposed Clifford circuits augmented matrix product states (CA-MPSs) [X. Qian, J. Huang, and M. Qin, Phys. Rev. Lett. 133, 190402 (2024)PRLTAO0031-900710.1103/PhysRevLett.133.190402] seamlessly augment density renormalization groups with circuits. In CA-MPSs, the entanglement from stabilizers is transferred to circuits, which can be easily handled according Gottesman-Knill theorem. As a result, an MPS needs only deal nonstabilizer entanglement, largely reduces bond dimension resource required for accurate simulation of many-body systems. this Letter, we generalize CA-MPSs framework time-dependent variational principle (TDVP) time evolution simulations. method, apply resulting in each TDVP step two-site sweeping process similar as groups, aiming at reducing entropy MPS, Hamiltonian transformed accordingly using chosen Similar does not increase number terms Hamiltonian, makes overhead very small new method. We test method XXZ chain, 2D Heisenberg model, Kitaev honeycomb model. results show that reduce hence reliable longer time. provides useful tool systems future.

Language: Английский

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Bilayer $t$-$J$-$J_\perp$ Model and Magnetically Mediated Pairing in the Pressurized Nickelate La$_3$Ni$_2$O$_7$

arXiv (Cornell University), Journal Year: 2023, Volume and Issue: unknown

Published: Jan. 1, 2023

The recently discovered nickelate superconductor La$_3$Ni$_2$O$_7$ has a high transition temperature near 80 K under pressure, which offers additional avenues of unconventional superconductivity. Here with state-of-the-art tensor-network methods, we study bilayer $t$-$J$-$J_\perp$ model for and find robust $s$-wave superconductive (SC) order mediated by interlayer magnetic couplings. Large-scale density matrix renormalization group calculations algebraic pairing correlations Luttinger parameter $K_{\rm SC} \simeq 1$. Infinite projected entangled-pair state method obtains nonzero SC directly in the thermodynamic limit, estimates strong strength $\bar{\Delta}_z \sim \mathcal{O}(0.1)$. Tangent-space tensor simulations further determine $T_c^*/J \mathcal{O}(0.1)$ clarify evolution order. Because intriguing orbital selective behaviors Hund's rule coupling compound, spin exchange (while negligible hopping), greatly enhances system. Such magnetically also been observed optical lattice ultracold atoms. Our accurate comprehensive reveal shed light on high-$T_c$ superconductivity pressurized La$_3$Ni$_2$O$_7$.

Language: Английский

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Time-Dependent Variational Principle with Controlled Bond Expansion for Matrix Product States

Physical Review Letters, Journal Year: 2024, Volume and Issue: 133(2)

Published: July 9, 2024

We present a controlled bond expansion (CBE) approach to simulate quantum dynamics based on the time-dependent variational principle (TDVP) for matrix product states. Our method alleviates numerical difficulties of standard, fixed-rank one-site TDVP integrator by increasing dimensions fly reduce projection error. This is achieved in an economical, local fashion, requiring only minor modifications standard implementations. illustrate performance and accuracy CBE-TDVP with several examples finite lattices, including new results bipolaron formation Peierls-Hubbard model spin pumping via adiabatic flux insertion chiral liquid.

Language: Английский

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Plaquette Singlet Transition, Magnetic Barocaloric Effect, and Spin Supersolidity in the Shastry-Sutherland Model

Physical Review Letters, Journal Year: 2023, Volume and Issue: 131(11)

Published: Sept. 14, 2023

Inspired by recent experimental measurements [Guo et al., Phys. Rev. Lett. 124, 206602 (2020PRLTAO0031-900710.1103/PhysRevLett.124.206602); Jiménez Nature (London) 592, 370 (2021)NATUAS0028-083610.1038/s41586-021-03411-8] on frustrated quantum magnet SrCu_{2}(BO_{3})_{2} under combined pressure and magnetic fields, we study the related spin-1/2 Shastry-Sutherland model using state-of-the-art tensor network methods. By calculating thermodynamics, correlations, susceptibilities, find, in zero field, not only a line of first-order dimer-singlet to plaquette-singlet phase transition ending with critical point, but also signatures ordered its end point terminating this line. Moreover, uncover prominent barocaloric responses, novel type correlation induced cooling effect, strongly fluctuating supercritical regime. Under finite identify from spin supersolid that breaks simultaneously lattice translational rotational symmetries. The present findings are accessible current experiments would shed new light phenomena archetypal SrCu_{2}(BO_{3})_{2}.

Language: Английский

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Scalable tensor network algorithm for thermal quantum many-body systems in two dimensions

Physical review. B./Physical review. B, Journal Year: 2025, Volume and Issue: 111(7)

Published: Feb. 19, 2025

Language: Английский

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