Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session S29: Strongly Correlated Systems, Including Quantum Fluids and Solids XV |
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Sponsoring Units: DCMP Chair: Yang Ge, University of Cincinnati Room: Room 221 |
Thursday, March 9, 2023 8:00AM - 8:12AM |
S29.00001: Effect of interactions on quantum oscillations in Kondo insulators Abhisek Samanta, Sumilan Banerjee, Mohit Randeria Hybridization-gap insulators provide a mean-field model for studying quantum oscillations in Kondo insulators. Our recent work [1] has revealed that density of states (SdH) and magnetization oscillations (dHvA) in such systems exhibit different frequencies and different field and temperature-dependent amplitudes, in marked contrast with metals. Kondo insulators are, however, strongly correlated systems where interaction effects cannot be a priori ignored. In this work, we generalize the periodic Anderson model with Sachdev-Ye-Kitaev SYK-like interactions for the f-electrons. We study the fate of quantum oscillations in Kondo insulators in this solvable limit. |
Thursday, March 9, 2023 8:12AM - 8:24AM |
S29.00002: Non-Fermi liquid behavior and quantum criticality in cubic heavy fermion systems with non-Kramers multipolar local moments Daniel J Schultz, SangEun Han, Yong Baek Kim Notable non-Fermi liquid and quantum critical behaviors are observed in rare-earth metallic systems with non-Kramers local moments supporting a number of different multipolar moments. A prominent example is Pr(Ti,V)2Al20, where the non-Kramers doublet of the Pr3+ ion allows quadrupolar and octupolar moments, but lacks a dipolar moment. Previous theoretical studies show that a single impurity Kondo problem with such an unusual local moment leads to novel non-Fermi liquid states. In this work, we investigate possible quantum critical behaviors arising from the competition between non-Fermi liquid states and multipolar-ordered phases induced by the RKKY interaction. We consider a local version of the corresponding Kondo lattice model, namely the Bose-Fermi Kondo model. Here, the multipolar local moments are coupled to fermionic and bosonic bath degrees of freedom representing the multipolar Kondo effect and RKKY interactions. Using a perturbative renormalization group (RG) study up to two loop order, we find critical points between non-Fermi liquid Kondo fixed points and a quadrupolar ordered fixed point. The critical points describe quantum critical behaviors at the corresponding phase transitions and can be distinguished by higher order corrections in the octupolar susceptibility that can be measured by ultrasound experiments. Our results imply the existence of a rich expansion of the phases and quantum critical behaviors in multipolar heavy fermion systems. |
Thursday, March 9, 2023 8:24AM - 8:36AM |
S29.00003: Spinful double-dot-cavity system as a nonlocal Kondo phase transition simulator Lidia Stocker, Michael S Ferguson, Oded Zilberberg Double quantum dot devices are well-established quantum simulation platforms. The dots emulate localised magnetic impurities that showcase Kondo-like hybridisations with their respective environment while competing with direct dot-dot coupling mediated by Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions. Here, we consider a double-dot device in which whispering gallery modes in a 2DEG form an all-electronic dot-cavity-dot system [Phys. Rev. Lett. 120, 236801 (2018)]. In this dot-cavity-dot system, we theoretically describe and predict (i) the experimentally observed coherent coupling between the two distant dots, where the cavity meditates their hybridisation, (ii) conventional Kondo effects, where the dots separately form a singlet with their coupled reservoir, (iii) a nonlocal Kondo effect, where the dot-cavity-dot impurity forms a magnetic state that spans over the full device, which in turn is screened by the reservoir. We furthermore study the robustness of the effects in the presence of spin decoherence and temperature scaling. Thus, we fully characterise the crossover between the (i)-(iii) phases. Our results pave the way for the experimental observation of nonlocal Kondo-like phase transitions and the realisation of exotic nonlocal magnetic impurities in mesoscopic devices. |
Thursday, March 9, 2023 8:36AM - 8:48AM |
S29.00004: Kondo screening cloud in a superconductor Ireneusz Weymann, Pascu Moca, Miklos Werner, Anand Manaparambil, Gergely Zarand Magnetic impurities embedded in a metal are screened by the Kondo effect, signaled by the formation of an extended correlation cloud, the so-called Kondo screening cloud. In a superconductor, the Kondo state turns into subgap Yu-Shiba-Rusinov states, and a quantum phase transition occurs between screened and unscreened phases once the superconducting energy gap exceeds sufficiently the Kondo temperature. Here, we show that, although the Kondo state does not form in the unscreened phase, the Kondo cloud does exist in both quantum phases. However, while screening is complete in the screened phase, it is only partial in the unscreened phase. Compensation, a quantity introduced to characterize the integrity of the cloud, is universal, and shown to be related to the magnetic impurities' g factor, monitored experimentally by bias spectroscopy. We also extend the analysis to the case of larger spin impurities, where more exotic types of Kondo states can develop. |
Thursday, March 9, 2023 8:48AM - 9:00AM |
S29.00005: Colossal Magnetoresistance and an Hierarchy of Competing Orders in the Rare Earth Zintl Semiconductor Eu5Sn2As6 Kohtaro Yamakawa, Ryan P Day, James G Analytis We investigate the rare earth Zintl semiconductor Eu5Sn2As6, a compound in a family of materials predicted to be magnetic topological insulators [1]. We find a colossal negative magnetoresistance spanning almost four orders of magnitude and, using electrical transport, magnetization, and heat capacity measurements, reveal a rich phase diagram in temperature and field. Magnetoresistance and non-linear electrical transport measurements help unveil the role of magnetic polarons on electrical transport and on the magnetic structure. Mechanisms through which the magnetic polarons may interact are discussed as well as investigations of the predicted topological character of the material. |
Thursday, March 9, 2023 9:00AM - 9:12AM |
S29.00006: Tunable heavy fermions in a moiré Kondo lattice Wenjin Zhao, Bowen Shen, Zui Tao, Zhongdong Han, Kaifei Kang, Kenji Watanabe, Takashi Taniguchi, Kin Fai Mak, Jie Shan The formation of heavy electrons by merging a lattice of local magnetic moments to a sea of itinerant electrons is a profound problem in condensed matter physics. The emergence of moiré materials provides a new platform to explore this problem in simple and tunable fashions. Here we report the realization of a tunable Kondo lattice in AB-stacked MoTe2/WSe2 moiré bilayers. Heavy electrons are formed when the MoTe2 layer is tuned to a strongly correlated Mott insulator, which supports a triangular lattice of local magnetic moments, and the WSe2 layer is doped with itinerant carriers. Over ten-fold enhancement in the electron mass is observed when the itinerant carriers and local moments form Kondo singlets. The Kondo singlets can be destroyed by an external magnetic field; a sharpened destruction at low temperatures suggests the presence of quantum criticality. Our study lays the foundation for exploring the Doniach phase diagram in semiconductor moiré materials. |
Thursday, March 9, 2023 9:12AM - 9:24AM |
S29.00007: Complexity of topologically frustrated systems Salvatore M Giampaolo, Fabio Franchini, Alberto Giuseppe Catalano In my talk, I will present a summary of our main results about the complexity of the ground states of topologically frustrated systems. A topological frustration arises when, in a short-range antiferromagnetic system made of an odd number of spins, periodic boundary conditions are considered. We characterize the increment of the ground state complexity exploiting different approaches as the analysis of the non-stabilizerness (or "magic") and of the stochastic irreversibility of the entanglement. |
Thursday, March 9, 2023 9:24AM - 9:36AM |
S29.00008: a variational wavefunction for weak Mott insulator and pseudogap metal using ancilla qubits Boran Zhou, Ya-Hui Zhang Ancilla qubits wave function was proposed [Phys Rev R, 023172 (2020)] to describe the pseudogap phase in the hole doped cuprates. In the ansatz, the original physical layer is accompanied by two hidden layers, on which the ancilla qubits reside. The physical wave function can be represented by projecting a slater determinant for three layers to the physical layers with each site's ancilla qubits forming a local singlet. |
Thursday, March 9, 2023 9:36AM - 9:48AM |
S29.00009: Preparation of Quantum Critical States with Machine Learning Donggyu Kim Preparation of entangled many-body states is one of the most important steps in quantum simulation, and yet its difficulty and complexity are significantly increasing with amounts of entanglement of a target many-body state. To overcome the difficulty and complexity, we propose a strategy to prepare entangled many-body states with machine learning with scaling relations and apply it to several quantum critical states. For example, in the transverse-field Ising model with 40 qubits, our construction gives a state close to the exact state, manifested by the central charge of 0.497. We also discuss how our strategy can be implemented in quantum simulations with trapped ions and Rydberg atoms. |
Thursday, March 9, 2023 9:48AM - 10:00AM |
S29.00010: Spectroscopic imaging of a magnetic-field-induced Lifshitz transition in Sr3Ru2O7 Peter Wahl, Carolina A Marques, Luke C Rhodes, Izidor Benedi?i?, Masahiro Naritsuka, Aaron B Naden, Zhiwei Li, Alexander C Komarek, Andrew Mackenzie The phenomenology and radical changes seen in materials properties traversing a quantum phase transition has captivated condensed matter research. Strong electronic correlations lead to novel ground states, including magnetic order, nematicity and unconventional superconductivity. To provide a microscopic model for these requires detailed knowledge of the electronic structure in the vicinity of the Fermi energy, promising a complete understanding of the physics of the quantum critical point. The strontium ruthenates provide an ideal material system to explore this physics using spectroscopic techniques, providing high-quality atomically flat surfaces. Spectroscopic confirmation of the energy and field-dependence of the electronic structure would allow verification of this scenario, as well as assessing the role of quantum fluctuations. Here, we demonstrate such a measurement using scanning tunneling microscopy at temperatures below 100mK.1 |
Thursday, March 9, 2023 10:00AM - 10:12AM |
S29.00011: NMR Signal Wipeout as a Probe of Quantum Fluctuations in TmVO4 Yu-Hsuan Nian, T. Greene, I. Vinograd, R. Singh, P. Massat, I. Fisher, N. J Curro TmVO4 is a model system for investigating the transverse field Ising model. This material undergoes ferroquadrupolar ordering below 2.3K due to an Ising-coupling between Tm quadrupolar couplings. This order can be destroyed via a transverse field along the crystalline c-axis. We probe the behavior of this system via V-51 NMR as a function of temperature and field along the c-axis. We find that the NMR spin echo intensity is dramatically reduced near the critical field, and that this behavior extends up to temperatures that exceed the critical temperature in zero transverse field. We argue that this behavior arises due to a unique hyperfine coupling that enables us to interpret the spin echo in terms of the time-dependence of the wavefunction of the environment of Tm quadrupolar moments. We confirm our behavior via spin lattice relaxation measurements that reveal a field-dependent gap opening above the critical field. |
Thursday, March 9, 2023 10:12AM - 10:24AM |
S29.00012: Relating non-Hermitian and Hermitian quantum systems at criticality Po-Yao Chang, Hsieh Chang-Tse We demonstrate three different transformations that relate Hermitian and non-Hermitian quantum systems at criticality. For the case preserving both the physical spectrum (PS) and the entanglement spectrum (ES), the entanglement entropy properties are identical for both Hermitian and non-Hermitian systems. In terms of the conformal field theory (CFT), the corresponding central charges extracted from the logarithmic scaling of the entanglement entropy are identical for both Hermitian and non-Hermitian systems. The second transformation preserves the PS but not the ES. The entanglement entropy scalings are different and lead to different central charges. We demonstrate this transformation by the dilation method for the free fermion cases, where the central charge c = −2 system can be mapped to c = 1 system. The last one is the Galois conjugate transformation that does not preserve both PS and ES. We demonstrate the Galois conjugate transformation in the anyonic golden chain model. The tricritical Ising model/3-state Potts mode can relate to the Lee-Yang model with negative central charges. |
Thursday, March 9, 2023 10:24AM - 10:36AM |
S29.00013: Uncovering conformal symmetry in the 3D Ising transition I: State-operator correspondence Yin-Chen He, Wei Zhu, Chao Han, Emilie Huffman, Johannes S Hofmann The 3D Ising transition, the most celebrated and unsolved critical phenomenon in nature, has long been conjectured to have emergent conformal symmetry. Conformal symmetry is believed to be a key ingredient for finding the long sought-after exact solution of the 3D Ising transition, but its emergence at the transition has rarely been explored directly, mainly due to unavoidable mathematical or conceptual obstructions. Here, we design an innovative way to study the quantum version of 3D Ising phase transition on the sphere, using the ``fuzzy (non-commutative) sphere" regularization. We accurately calculate and analyze the energy spectra at the transition, and demonstrate the state-operator correspondence (i.e. radial quantization), an important property of conformal field theory. Our result directly elucidates the emergent conformal symmetry of the 3D Ising transition, a conjecture made by Polyakov half a century ago. |
Thursday, March 9, 2023 10:36AM - 10:48AM |
S29.00014: Uncovering conformal symmetry in the 3D Ising transition II: Conformal fields and operator contents Liangdong hu, Wei Zhu, Chao Han, Yinchen He At a quantum critical point, the low-energy physics of a transverse Ising model is described by conformal field theory (CFT). Based on the newly-discovered Hamiltonian for 3D Ising transition, we build an approximate lattice representation of the corresponding primary CFT operators. We then numerically compute the operator product expansion coefficients governing the fusion of two primary fields. The obtained conformal data starting from a microscopic description nicely agrees with that from conformal boostrap. |
Thursday, March 9, 2023 10:48AM - 11:00AM |
S29.00015: Uncovering conformal symmetry in the 3D Ising transition III: critical phenomena on a quantum fuzzy sphere Wei Zhu, Liangdong Hu, Chao Han, Yinchen He We describe how to determine the quantum phase diagram of newly-discovered Hamiltonian for 3D Ising transition on fuzzy sphere through the conventional finite size scaling scheme. The phase transition point is determined by the Ising order parameter and the binder ratio. We implement the calculations using large-scale density-matrix renormalization group algorithm. |
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