Strongly Correlated Electrons
Multiorbital Anisotropy and Magnetic Excitations in Trilayer Nickelate Pr$_4$Ni$_3$O$_{10}$
Ziqiang Guan, Sophia F. R. TenHuisen, Xuefei Guo et al. (+9 more)
Rare-earth substitution strongly modifies the structure,
metallicity, and superconducting behavior of Ruddlesden-Popper (RP) nickelates, but its impact on their
magnetic interactions remains unclear. Here, we combine x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) to resolve the multiorbital electronic structure and
magnetic excitations of Pr$_4$Ni$_3$O$_{10}$. The absence of an overlapping rare-earth resonance provides direct access to the Ni $L_3$ edge, while polarization-dependent measurements at the Ni $L$- and O $K$-edges resolve distinct planar and out-of-plane Ni-O hybridization channels. Momentum-resolved RIXS reveals dispersive
magnetic excitations that soften toward the incommensurate
spin-density-wave wave vector. An effective
spin-wave analysis yields a sizable intra-trilayer exchange coupling, comparable to the leading in-plane interactions and robust against rare-earth substitution. Our results identify the multilayer architecture, rather than rare-earth substitution alone, as a key control knob of the
magnetic interactions in these materials.
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All authors Ziqiang Guan, Sophia F. R. TenHuisen, Xuefei Guo, Wei He, Aulden K. Jones, Marli dos Reis Cantarino, Xinglong Chen, Hong Zheng, J. F. Mitchell, Nicholas B. Brookes, Mark P. M. Dean, Matteo Mitrano
Strongly Correlated Electrons
Ambipolar metal-insulator transition in bilayer MoSe2
Ha-Leem Kim, Hyungbin Lim, Terry Wu et al. (+7 more)
When Coulomb interactions dominate kinetic energy, dilute two-dimensional carriers form a Wigner solid. Both its melting and disorder-driven localization can drive density-tuned metal-
insulator transitions, but their relative roles and interplay have been debated for decades. Atomically thin
semiconductors offer a new test because transport and scanning tunneling microscopy can probe the same material, yet poor contacts impede transport where correlations are strongest. Here we introduce contact-free
radio-frequency reflectometry that senses sheet resistance through capacitive gate coupling. It resolves the electron and previously inaccessible hole transitions in the same bilayer MoSe2 device, whose carriers share disorder but not mass. Their critical densities differ fourfold yet correspond to comparable Coulomb-to-kinetic-energy ratios, where tunneling microscopy finds solid-
liquid coexistence. Magnetoresistance peaks sharply at each transition, reflecting a Pomeranchuk-like, field-driven expansion of the Wigner solid against the correlated
liquid. Our results demonstrate interaction-driven transitions in high-quality two-dimensional
semiconductors, opening quantitative transport in contact-limited systems.
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All authors Ha-Leem Kim, Hyungbin Lim, Terry Wu, Amogh Y. Waghmare, Garima Gupta, Takashi Taniguchi, Kenji Watanabe, Archana Raja, Eric Y. Ma, Feng Wang
Strongly Correlated Electrons
From continuum neural quantum states to effective lattice models: Fluctuating Wigner molecules in moiré superlattices
Ahmed Khalifa and Shubhayu Chatterjee
Effective descriptions of
quantum materials rely on a separation of energy scales that identifies their low-energy degrees of freedom. When kinetic energy,
lattice potential, and interactions compete, this hierarchy breaks down, and both the microscopic state and its effective description are unknown. Continuum neural
quantum states (NQS) can find the ground state directly without projecting onto prescribed bands, orbitals, or
spins, but their microscopic wavefunctions are difficult to interpret in terms of effective variables. Here, we introduce a wavefunction readout that maps the continuum NQS onto site-resolved charge and
spin statistics, allowing effective degrees of freedom to emerge from the microscopic solution. Focusing on moiré transition metal dichalcogenides at filling $\nu = 3$, the NQS reveals a low-
spin ground state below the ferromagnetic
crystal of
spin-polarized Wigner molecules. Although the charge density retains triangular molecular motifs, our readout reveals significant charge fluctuations through bound nearest-neighbor doublon–hole pairs. Each molecular charge state has an inert
spin-singlet core and rim electrons that carry the
spin. Charge and
spin fluctuations are therefore intertwined, with antiferromagnetic
spin-correlations between sites, motivating an effective description by a spinful two-orbital Hubbard model. More generally, our results demonstrate a route from continuum wavefunctions to effective
lattice models when competing scales preclude a controlled reduction.
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Strongly Correlated Electrons · Cross-listed from cond-mat.supr-con
Remote magnon sensing detects the universal phase stiffness jump in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$
Yue Sun, Mai Nguyen, Naiyuan James Zhang et al. (+14 more)
Phase stiffness governs macroscopic
quantum coherence in superfluids and
superconductors, providing a sensitive probe of condensate depletion, fluctuations, and phase transitions. However quantitative and spatially resolved measurements remain challenging. Here we report a contactless, local, all-optical measurement of superconducting phase stiffness using propagating antiferromagnetic
magnons as remote sensors. In CrSBr, strong
exciton-
magnon coupling enables optical excitation and detection of
magnon wavepackets and precise determination of their group velocity. When CrSBr is interfaced with underdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, we find that the
magnon group velocity is substantially enhanced below the superconducting transition and quantitatively encodes the phase stiffness through Meissner screening currents. Using this capability, we identify a parallel-field-induced Berezinskii-Kosterlitz-Thouless transition through direct observation of the universal phase-stiffness jump, revealing a field-controlled route to expose intrinsic two-dimensional phase-ordering physics in a bulk cuprate. Our work establishes propagating
magnons as local probes of superconducting electrodynamics and phase-coherent phenomena in low-dimensional
quantum materials.
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All authors Yue Sun, Mai Nguyen, Naiyuan James Zhang, Dingbin Huang, Shuai Yuan, Aljoscha Söll, Arun Ramanathan, Takashi Taniguchi, Kenji Watanabe, Xavier Roy, Zdeněk Sofer, Shigeyuki Ishida, Hiroshi Eisaki, Makoto Hashimoto, Zhi-Xun Shen, Joseph Orenstein, Xiaodong Xu
Strongly Correlated Electrons
Exact solutions for kinematics across interaction-deformed Fermi surfaces
Alexander Kruchkov and F. Duncan M. Haldane
Luttinger's
theorem fixes the volume of the Fermi sea of a Fermi
liquid, but not how interactions redistribute occupation around its surface. For an interaction switched on and tuned at fixed density, we derive the exact rates of change of the occupation deficit inside the interacting Fermi surface and of the surplus outside it. Each is the weight swept by the deforming surface plus a change of Luttinger's integrand at fixed momentum; the difference of the surface terms is flux of incoherent weight $1 - Z_{\vec k}$. These identities hold with or without the Luttinger
theorem.
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Strongly Correlated Electrons
Zero Mode Operators and Charge-Conjugation Defects in Non-Abelian Fractional Quantum Hall-Superconductor Heterostructures
Junyi Cao and Eduardo Fradkin
We study zero modes bound to charge-conjugation defects in fractional
quantum Hall-
superconductor (FQH-SC)
heterostructures built from Abelian and non-Abelian FQH states. Although the associated defects are well described by $G$-crossed braided tensor categories, a local operator description of their zero modes is not generally known. We generalize the bulk-to-boundary construction of localized zero mode operators to FQH-SCs with non-Abelian parent topological orders, mapping bulk Wilson operators in the folded theory to localized zero mode operators in the one-dimensional FQH-SC theory. This construction distinguishes zero mode anyons from the local zero mode operators that act on the defect
Hilbert space and yields a generalized zero mode
algebra. It also determines the fusion-channel dependence of tunneling: tunneling of zero mode operators probes bulk monodromy, while direct zero mode anyon transfer probes $G$-crossed associativity data. Applying this framework, we recover the $\mathbb{Z}_{2m}$ parafermion zero mode structure of fermionic Laughlin FQH-SCs at filling $\nu=1/m$, obtain a $\mathbb{Z}_2^{(n)}\times\mathbb{Z}_N$ structure for generalized Moore-Read states at filling $\nu=1/m$, with $N=2m$ for fermionic states and $N=m$ for bosonic states, and find a $\mathrm{Fib}\times\mathbb{Z}_N$ structure for the $k=3$ Read-Rezayi state at filling $\nu=3/(3M+2)$, with $N=2(3M+2)$ for fermionic states and $N=(3M+2)/2$ for bosonic states. In the Read-Rezayi case, zero mode operator tunneling and direct zero mode anyon transfer yield distinct universal amplitude ratios between the neutral fusion channels, providing a characteristic signature of the underlying Fibonacci defect structure.
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Strongly Correlated Electrons
Chiral Central Charge from Real-Space Twist Operator Correlator
Yunlong Zang
Recent years have witnessed substantial progress in the
entanglement-based characterization of
quantum phases of matter, with growing interest in real-space formulas due to their theoretical and experimental relevance. For two-dimensional gapped
quantum systems, we propose a universal real-space formula for the chiral central charge based on the twist-operator correlator $Z_{g,h}=\langle\psi^{(N)}\rvert\mathcal{T}_A(g)\mathcal{T}_B(h)\mathcal{T}_C(g)\mathcal{T}_C(h)\lvert\psi^{(N)}\rangle$, where $\lvert\psi^{(N)}\rangle=\lvert\psi\rangle^{\otimes N}$ is the $N$-copy state and $g,h\in S_N$ are permutations. The twist operator $\mathcal{T}_R(g)$ permutes the $N$ replicas within region $R$ according to $g$. For pairs $(g,h)$ satisfying the spherical condition, we show that the phase of the correlator is determined by the chiral central charge $\mathfrak{c}_{-}$ through $Z_{g,h}/\left\lvert Z_{g,h}\right\rvert=(\theta_g\theta_h/\theta_{gh})^{\mathfrak{c}_{-}}$, where $\theta_g^{\mathfrak{c}_{-}}$ is the topological
spin of the twist defect labeled by $g\in S_N$. The construction applies to both bosonic and fermionic systems. We derive the formula within a field-theoretic framework under suitable assumptions and further test it numerically in microscopic
lattice models. Our results establish a universal connection between real-space
entanglement structures and the chiral central charge, providing a systematic framework for characterizing chiral topological phases directly on the
lattice.
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Strongly Correlated Electrons · Cross-listed from cond-mat.mes-hall
Quantum twisting microscopy as a momentum-resolved probe of quantum geometry and sublattice symmetries
Lucas V. Pupim and Mathias S. Scheurer
In two-dimensional (2D) flat-band systems, as engineered, for instance, by stacking and twisting van der Waals materials, the momentum dependence of the Bloch states is a key factor in determining the interaction-induced emergence of different phases. Hence, methods of probing this form of ”
quantum geometry” are crucial to understanding these systems. Yet, extracting the momentum dependence of the underlying
quantum geometric tensor from measurements is challenging in 2D. Here, we propose employing a
quantum twisting microscope (QTM) with a sublattice-polarized tip to fill this gap. We show how expectation values of sublattice Pauli
matrices can be probed across the scanned momentum path. This allows for the direct measurement of crucial
symmetries characterizing the different candidate instabilities in
graphene-based moiré systems. We furthermore show that the
quantum metric component along the scan direction can also be extracted; the full
quantum geometric tensor is also accessible, given that more than one sublattice polarization can be used. Our work illustrates the potential and extends the versatility of the QTM approach. If implemented in future experiments, this would provide unprecedented access to the
symmetry signatures of the correlated phases and to the underlying
quantum geometry in twisted bilayer
graphene and related systems.
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Strongly Correlated Electrons · Cross-listed from quant-ph
Entanglement manipulation and magic area-laws
Rafael A. Macedo and Rafael Chaves
Physical many-body
quantum systems typically interact locally, giving rise to ground states where
entanglement grows with the area of the region being probed. Beyond
entanglement, non-stabilizerness (or "magic") has been established as another crucial resource linked to
quantum complexity and the properties of error-correcting states. Unlike
entanglement, non-stabilizerness typically behaves with a volume-law scaling in ground states, indicating inherent computational complexity. In this work, we show that under a recent classification of
quantum states, area-law states split into two distinct classes.
Entanglement-dominated states obey an area-law for non-stabilizerness and admit efficient
quantum algorithms for
entanglement manipulation. Conversely, magic-dominated states exhibit a a faster-than-area growth of subsystem non-stabilizerness and require non-efficient
algorithms for
entanglement manipulation tasks. Within this context, we introduce the concept of the stabilizer regime, a restricted
quantum phase that admits efficient
entanglement manipulation and hosts area laws for both magic and
entanglement.
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Strongly Correlated Electrons
Ghost rotationally invariant slave-boson approach to response functions
Tsung-Han Lee, Corey Melnick, Nicola Lanatà et al. (+1 more)
We propose a finite-temperature Gaussian-fluctuation formalism for response functions within ghost rotationally invariant slave-
boson (gRISB) theory and apply it to the two-dimensional Hubbard model. The gRISB
magnetic phase boundary and static
spin and charge susceptibilities capture the trends of dynamical mean-field theory (DMFT), significantly improving upon standard RISB and the random phase approximation (RPA). At the RISB level, our formalism recovers the Kotliar-Ruckenstein response. The dynamical susceptibilities resolve paramagnons, low-energy sound modes, and high-energy Hubbard excitations. Because they are evaluated directly on the real-frequency axis, the results avoid Matsubara truncation,
stochastic sampling, and numerical analytic continuation. We also introduce a conserving quasiparticle approximation that expresses the response in terms of dressed Green's functions and vertex corrections.
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All authors Tsung-Han Lee, Corey Melnick, Nicola Lanatà, Gabriel Kotliar
Strongly Correlated Electrons · Cross-listed from cond-mat.mes-hall
Quasiparticle-resolved variational theory of Andreev spin qubits
Teodor Iličin and Rok Žitko
An Andreev
spin qubit stores a single unpaired
spin, yet its coupling to the superconducting phase can be dominated by coherent virtual quasiparticle pairs. We develop a continuum variational description of the odd-parity doublet in a
quantum-dot Josephson junction with Coulomb interaction and
spin-dependent background tunneling. Retaining configurations with up to two Bogoliubov quasiparticles provides compact analytical expressions for energies and wavefunctions. We
benchmark the results against numerical renormalization group calculations and identify sources of error. We obtain closed-form expressions for the conventional and
spin-dependent Josephson couplings. Despite their small probability, two-quasiparticle configurations, through coherence with the zero-quasiparticle component, supply exactly half of the leading
spin-dependent Josephson coupling even without Coulomb repulsion and dominate it as the repulsion grows.
Spin-orbit-induced
spin transfer between the dot and the leads produces a Josephson-current contribution that is common to both
qubit states and finite at zero phase bias when the dot and lead Zeeman energies differ. We also map the localization of the virtual quasiparticles and the
spin density in the leads. The results connect strongly correlated
quantum-dot models to effective
Hamiltonians used for Andreev-
spin-
qubit circuits and clarify how the wavefunction structure determines their couplings.
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Strongly Correlated Electrons
Dynamical vertex approximation for retarded interactions: Application to the Hubbard-Holstein model
Emin Moghadas, Samuele Giuli, Massimo Capone et al. (+1 more)
We extend the dynamical vertex approximation (D$\Gamma$A), in its most commonly used ladder-version, to systems with retarded electronic interactions. Such an extended scheme, which we name "dynamical-$U$ D$\Gamma$A", allows us to study strongly interacting electrons coupled to
bosons including non-local spatial correlations on all length scales on top of the purely local ones captured by dynamical mean-field theory. We demonstrate the applicability of the method in the specific case of the coupling to a single dispersionless phononic mode, by studying the Hubbard-Holstein model on the square and cubic
lattices, focusing on regimes of sizable Hubbard interactions where strong electronic correlations compete with
phonon-mediated interactions. As illustrative examples, we consider the antiferromagnetic phase in the three-dimensional model and the d-wave
superconductor in two dimensions, analyzing the effect of the electron-
phonon coupling, including its frequency dependence, on both instabilities.
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All authors Emin Moghadas, Samuele Giuli, Massimo Capone, Alessandro Toschi
Strongly Correlated Electrons · Cross-listed from cond-mat.stat-mech
Replica Fragmentation and Glassy Dynamics in Parity Learning
Han Ma
We study how independently trained
Transformer neural networks reconstruct a binary string from its local domain walls. Runs sharing the data and training protocol can realize different functions. We treat them as replicas and measure truth
alignment $m$, prediction confidence $q_{\mathrm{self}}$, and cross-replica agreement $q_{\mathrm{cross}}$. Confident disagreement defines the finite-size replica fragmentation that we call glass-like. With small training sets, replicas predict all training examples correctly but remain confident in incorrect predictions for unseen inputs, a regime we call memorization. With larger sets, runs can generalize and then retreat. Retreat occurs when outputs start to deviate from truth while confidence remains high. The frontier between learned and unlearned outputs recedes toward shorter strings. Many later recover as the frontier advances again. The self–cross gap $q_{\mathrm{self}}-q_{\mathrm{cross}}$ clearly distinguishes the three learning regimes of memorization, retreat, and recovery. With overall and position-dependent truth
alignment subtracted, their residual correlations also differ: memorizing replicas have weakly and uniformly correlated residuals, while retreat has the largest fraction of replica pairs whose residuals are anti-correlated. That is, on the inputs where one replica of such a pair does better than its average, the other tends to do worse. These finite-size observations distinguish persistent memorization from ongoing retreat–recovery dynamics. The thermodynamic and long-time limits, and extensions to other learning tasks, remain open.
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Strongly Correlated Electrons
Incoherent Spectral Weight Emerging from a Van Hove Singularity in a Kagome Metal
C.-y. Lim, J. Deng, A. Korshunov et al. (+14 more)
Waterfall-like spectral features observed by angle-resolved photoemission spectroscopy (ARPES) are commonly associated with strong electronic correlations or electron-
boson coupling. Here, we investigate this connection in the kagome metal LuFe6Ge6, a structurally simple member of the FeGe-derived family, using polarization-dependent ARPES, density functional theory and dynamical mean-field theory. We observe a pronounced vertical spectral feature at the L point extending over several hundred meV in binding energy. Its orbital character is identified as predominantly Fe dyz, and its energy onset coincides with a van Hove singularity located approximately 0.3 eV below EF . Despite the waterfall-like spectral response, dynamical mean-field theory (DMFT) reveals only weak electronic correlations, while the calculated electronic structure closely reproduces the experimental bulk bands. We propose that the anomalous spectral weight may arise from inelastic scattering of the outgoing photoelectrons, potentially associated with the large density of states near the van Hove singularity. Our results suggest that waterfall-like features can emerge without strong electronic correlations and highlight the possible role of the underlying band structure and photoelectron energy-loss processes in their interpretation.
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All authors C.-y. Lim, J. Deng, A. Korshunov, A. Kar, D. Subires, H. Li, Y. Jiang, H. Hu, E. Modin, P. Törmä, A. Kumar-Sharma, C. Shekhar, A. Louat, T. K. Kim, C. Felser, B. Andrei Bernevig, S. Blanco-Canosa
Strongly Correlated Electrons · Cross-listed from cond-mat.supr-con
Quantum geometry of collective pairing fluctuations in the superfluid weight of multiband superconductors
R. N. Kalkan and M. Iskin
Beyond the frozen-pairing contribution, the superfluid weight of a multiband
superconductor contains a correction from the self-consistent relaxation of the pairing amplitudes under a phase twist. We show that this correction has a
quantum-
geometric origin, not in the space of Bloch states but in the space of collective pairing fields. For an attractive multiband Hubbard model at the mean-field level, the thermodynamic Hessian governing the pairing response coincides with the static Gaussian pair-fluctuation kernel at zero momentum at every temperature below $T_c$. Since gauge invariance relates a phase twist to a finite center-of-mass momentum of the pair field, the superfluid weight is set by the small-momentum
curvature of the
eigenvalue branch that evolves from the Goldstone mode, and the relaxation correction is a stiffness-weighted
quantum metric of the corresponding soft eigenvector on the
manifold of pairing configurations. The same construction yields the Ginzburg-Landau gradient coefficient with the identical
geometric correction, hence the coherence-length tensor, and, with the low-frequency dynamics of the kernel, the pair-mass tensor. Lieb-
lattice calculations verify the equivalence of the thermodynamic, fluctuation-kernel, and soft-mode formulations and the independence of the superfluid weight from the orbital
embedding.
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Strongly Correlated Electrons
Exchange self-energy and vertex corrections to static screening in the two-dimensional electron gas
Sankar Das Sarma
We compute analytically the leading beyond-ring corrections to the static irreducible polarizability of the two-dimensional (2D) electron gas, namely the two exchange self-energy diagrams and the exchange vertex diagram, each of first order in the Coulomb coupling, and insert the resulting polarizability into the RPA
geometric series to obtain the static dielectric function and screened interaction. The self-energy and vertex contributions individually diverge; we obtain both divergent pieces in closed form. Their sum is finite and reproduces exactly the Hartree-Fock compressibility, which renormalizes the Thomas-Fermi wave vector. We show that exchange converts the one-sided 2D Kohn kink at 2k_F into a sharp two-sided peak, a qualitative improvement over Thomas-Fermi and RPA screening. In real space this makes the Friedel oscillations around a charged impurity 2-3 times larger than in RPA, with an amplitude that increases with distance over the range studied; implications for Kohn-Luttinger pairing are discussed. Relation to earlier works on the same diagrams is discussed.
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Strongly Correlated Electrons
Symmetry protected quantum many body scars through half-gauging
Weslei B. Fontana, Fabrizio G. Oliviero and Yi-Ping Huang
We study the interplay between
symmetry defects insertion and the phenomena of
quantum many body scarring. We exploit a class of models obtained from an
embedding mechanism that defines a
stochastic matrix form
hamiltonian, hosting zero energy many body scarred states. Such models display an interesting playground to explore the consequences of dualities, half-gauging operations and so on. We first show that inside this class of models, what are the conditions to still have scared states after defect insertion. The main result of our work is a detailed analysis of half-gauging in such chains, which introduces a non-trivial interface in our system, leading to scarred states protected by the underlying
symmetries. The conclusions for half-gauged scarred systems are general and may lead to fruitful directions for higher dimension scarred physics and their robustness.
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Strongly Correlated Electrons
Gradual Localization of Itinerant Cobalt 3d Electrons in the Pyrochlore Ferromagnetic Metal LuInCo4
Taiki Shiotani, Subaru Yoshimoto, Yoshikazu Tabata et al. (+6 more)
We investigated the microscopic
magnetic state of the itinerant-electron ferromagnet LuInCo4 with a cobalt pyrochlore
lattice by means of powder and single-
crystal neutron diffraction measurements. The powder
neutron diffraction profiles at zero field are well described by a simple q = 0 collinear ferromagnetic structure with an ordered Co moment of 0.9 uB. Single-
crystal neutron diffraction experiments further suggest the absence of both antiferromagnetic order and long-period helical
magnetic modulation. In addition, diffuse
magnetic scattering was observed around q = 0, with its intensity distribution gradually broadened in reciprocal space upon cooling. Based on these observations, we propose a possible microscopic origin of the low-temperature metamagnetic transition in terms of a ferromagnetic instability enhanced by gradual localization of the itinerant Co-3d electrons. These results suggest that LuInCo4 provides a model system for investigating the interplay between electron localization and itinerant-electron ferromagnetism in cobalt-based metallic pyrochlore compounds.
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All authors Taiki Shiotani, Subaru Yoshimoto, Yoshikazu Tabata, Yusuke Nambu, Katsuki Kinjo, Kazuhiro Nawa, Taku J. Sato, Takeshi Waki, Hiroyuki Nakamura
Strongly Correlated Electrons · Cross-listed from quant-ph
A Single Conformal Coordinate Decodes Outcome-Resolved Measurement-Induced Entanglement
Reyhaneh Khasseh and M.A. Rajabpour
A local measurement of a critical many-body state produces exponentially many microscopic outcomes, each defining a different conditioned
quantum state. We ask how much information from one such outcome is actually needed to predict the
entanglement that remains between two unmeasured regions. We show that, in critical
quantum chains, the universal outcome-resolved Rényi
entropy is asymptotically determined by a single compact conformal coordinate extracted directly from the measurement record. Compact-
boson theory explains this compression: the universal
entropy is insensitive to all spatially varying components of the boundary profile, retaining only a single relative compact zero mode. At the free-
fermion XX point, exact
lattice identities expose the microscopic structure underlying the decoder, while large-scale outcome-by-outcome calculations confirm its scaling prediction across different subsystem geometries and Rényi indices. Numerical calculations in interacting XXZ chains further show that the same microscopic coordinate continues to decode the conditional
entropy without interaction-dependent retuning. Thus an exponentially large space of measurement outcomes is reduced, for this universal observable, to a single conformal degree of freedom, revealing an emergent Luttinger-
liquid mechanism for outcome-resolved postmeasurement
entanglement.
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Strongly Correlated Electrons
Two-exciton bound states in the Merrifield exciton model
Ning Wu, Runtian Li and Dazhi Xu
Understanding the formation and dynamics of two-
exciton bound states (BSs) is crucial for harnessing multi-
exciton phenomena and designing next-generation organic
semiconductor materials. While various mechanisms such as intermolecular
exciton-
exciton interactions or multi-level intramolecular configurations can generate these BSs, a fundamental understanding of their underlying
lattice dynamics remains a key challenge. Within this context, the Merrifield
exciton model stands out as a premier framework for capturing the intricate
quantum mixing between single-site doubly-excited states and two-particle scattering continuum. In this work, by constructing a set of exact two-
exciton Bloch states and applying a plane-wave ansatz to treat the resulting inhomogeneous tridiagonal
matrices, we provide a complete, rigorous solution to the two-
exciton problem in a finite-size Merrifield chain. We analytically map the parameter regions that support two-
exciton BSs, proving that at most two distinct types of BSs can emerge, located either above or below the scattering continuum. Furthermore, we provide a quantitative interpretation of how these two types of BSs evolve as a function of the total wave number within the whole Brillouin zone. The obtained closed-form expressions for the eigenenergies and wave functions offer valuable
benchmarks for exploring
exciton dynamics and optical responses in related molecular aggregates.
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Strongly Correlated Electrons · Cross-listed from cond-mat.mes-hall
Bichargon Hall Effect
Ping Tang
The conventional Hall effect arises from the transverse deflection of mobile electronic charge carriers in conductors. Here, we predict a bosonic charge Hall effect in charge-ordered
insulators mediated by bichargons, collective bosonic excitations of charge order carrying quantized electric charges $\pm 2e$. In contrast to conventional electronic carriers, a thermally excited bichargon gas does not support dc electrical conduction in response to an external electric field despite its constituents carrying finite electric charges. We show that a temperature gradient can instead drive a diffusive flow of thermal bichargons, while an out-of-plane
magnetic field deflects the oppositely charged bichargons in opposite transverse directions via the Lorentz force, leading to a finite Hall charge current and opposite charge accumulations at the sample edges. Our results broaden the paradigm of charge Hall transport beyond conventional electronic conductors, establishing that a charge Hall response can emerge in an electrically insulating system through charged bosonic quasiparticles.
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Strongly Correlated Electrons · Cross-listed from cond-mat.supr-con
Luttinger Liquid Behavior in a Single-Layer Nickelate La1.4Sr0.6NiO4
Yinqi Hu, Yidian Li, Xian Du et al. (+19 more)
The discovery of high-temperature superconductivity in bilayer and trilayer nickelates has spurred intense interest in the Ruddlesden-Popper nickelates; yet the fundamental properties of the NiO2 layer remain obscured by interlayer coupling. It is therefore imperative to investigate the electronic properties of their single-layer counterpart to isolate the intrinsic physics of the NiO layer. In this work, we present a systematic study of the single-layer nickelate La1.4Sr0.6NiO4 using high-resolution angle-resolved photoemission spectroscopy (ARPES) and theoretical calculations. We reveal strong electron correlation effects, manifested by high-energy kinks in band dispersions and a pronounced orbital-dependent band renormalization. Interestingly, we observe a quasi-one-dimensional electronic structure characterized by straight Fermi surface sheets along the diagonal momentum directions. Such square Fermi surface
topology facilitates non-Fermi
liquid behavior consistent with the Luttinger
liquid model, as evidenced by the power-law spectral function, robust temperature scaling, and the observation of
spin-charge separation. Our results therefore not only unveil an exotic Luttinger
liquid behavior emerging from the unexpected dimensional reduction in an intrinsically quasi-two-dimensional nickelate but also provide a new perspective for understanding the intriguing physics in multilayer nickelates.
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All authors Yinqi Hu, Yidian Li, Xian Du, Wenxuan Zhao, Kaiyi Zhai, Senyao Zhang, Jiawei Shao, Mingxin Mao, Houke Chen, Jieyi Liu, Donghui Lu, Makoto Hashimoto, Fangyuan Zhu, Zhengtai Liu, Dawei Shen, Yaobo Huang, Zhongkai Liu, D. Prabhakaran, Yanpeng Qi, Yilin Wang, Yulin Chen, Lexian Yang