Article
Physics, Multidisciplinary
Hao Xie, Linfeng Zhang, Lei Wang
Summary: The newly developed neural canonical transformation approach provides a principled way to extract the effective mass of electron gas by calculating the thermal entropy at low temperature. Calculation reveals a suppression of effective mass in the two-dimensional spin-polarized electron gas, which is more pronounced than previous reports, and calls for experimental verification.
Article
Materials Science, Multidisciplinary
A. Goetz, S. Beyl, M. Hohenadler, F. F. Assaad
Summary: The two-dimensional Su-Schrieffer-Heeger model with electron-phonon coupling is investigated using Langevin dynamics and auxiliary-field quantum Monte Carlo. The efficient method in the challenging adiabatic limit is argued based on an explicit determination of the density of zeros of the fermion determinant. Large-scale simulations establish a transition from a (pi, pi) valence bond solid to an antiferromagnet as the phonon frequency increases. The single-particle spectrum shows renormalization and suggests the presence of a gapped polaronic band, while the particle-hole channels show gapless modes associated with long-range bond and magnetic order.
Article
Materials Science, Multidisciplinary
Massimo Boninsegni
Summary: The bound state of a He-3 atom at the interface between crystalline and superfluid phases of He-4 is investigated using first principle Quantum Monte Carlo simulations. The results show that the He-3 atom is sharply localized in a quasi-2D layer of He-4, located in the intermediate region between the solid and liquid states. The localization and quantum-mechanical exchanges of the He-3 atom are influenced by the attractive strength of the substrate.
RESULTS IN PHYSICS
(2022)
Article
Multidisciplinary Sciences
Andrew D. King, Jack Raymond, Trevor Lanting, Sergei V. Isakov, Masoud Mohseni, Gabriel Poulin-Lamarre, Sara Ejtemaee, William Bernoudy, Isil Ozfidan, Anatoly Yu. Smirnov, Mauricio Reis, Fabio Altomare, Michael Babcock, Catia Baron, Andrew J. Berkley, Kelly Boothby, Paul I. Bunyk, Holly Christiani, Colin Enderud, Bram Evert, Richard Harris, Emile Hoskinson, Shuiyuan Huang, Kais Jooya, Ali Khodabandelou, Nicolas Ladizinsky, Ryan Li, P. Aaron Lott, Allison J. R. MacDonald, Danica Marsden, Gaelen Marsden, Teresa Medina, Reza Molavi, Richard Neufeld, Mana Norouzpour, Travis Oh, Igor Pavlov, Ilya Perminov, Thomas Prescott, Chris Rich, Yuki Sato, Benjamin Sheldan, George Sterling, Loren J. Swenson, Nicholas Tsai, Mark H. Volkmann, Jed D. Whittaker, Warren Wilkinson, Jason Yao, Hartmut Neven, Jeremy P. Hilton, Eric Ladizinsky, Mark W. Johnson, Mohammad H. Amin
Summary: Experimental observations show that quantum simulation has a dynamic advantage over classical methods in simulations of geometrically frustrated magnets. This advantage increases with system size and inverse temperature, achieving a million-fold speedup over efficient CPU implementations. The study provides important evidence that near-term quantum devices can accelerate computational tasks of practical relevance.
NATURE COMMUNICATIONS
(2021)
Article
Computer Science, Software Engineering
Cheng Zhang, Zihan Yu, Shuang Zhao
Summary: This paper introduces a physics-based differentiable rendering technique that utilizes differential path integrals for estimating arbitrary scene parameters. The method efficiently handles challenging geometric discontinuities and light transport phenomena, such as volumetric caustics.
ACM TRANSACTIONS ON GRAPHICS
(2021)
Article
Materials Science, Multidisciplinary
G. Bouzerar
Summary: Research shows that flat bands in two-dimensional materials can pave the way for room-temperature ferromagnetism in 2D compounds. The magnetic exchanges between localized spins are largely dominated by the ferromagnetic contribution of the flat bands, and the crossover temperatures (ferromagnetic/paramagnetic phase transition) scale linearly with the local coupling, leading to temperatures higher by an order of magnitude compared to current experimental reports. High crossover temperatures could be achieved in micrometer-sized flat band systems.
Article
Physics, Multidisciplinary
Yu-Feng Song, Xiao-Jun Tan, Xin-Hang Zhang, Jesper Lykke Jacobsen, Bernard Nienhuis, Youjin Deng
Summary: In this study of percolation on a domain with the topology of a disc, a nested-path operator was introduced, connecting a continuous family of one-point functions to the structure's center. The power-law scaling behavior at criticality was observed, and an analytical formula for the exponent as a function of path fugacity was proposed based on numerical results. In addition, an identity for site percolation on the triangular lattice was discovered and proven to hold for self-matching lattices of any size.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Materials Science, Multidisciplinary
C. A. Perroni, G. De Filippis, V Cataudella
Summary: A different variational approach is proposed at zero temperature to study ground-state features of the Frohlich model including electron-electron and electron-phonon interactions. The electronic spectral function is calculated from weak to intermediate electron-phonon coupling regime, showing a transfer of spectral weight from the incoherent hump to the coherent peak. Three density regimes are identified: low densities with single large polaron characteristics, intermediate densities with a rapid crossover from incoherent to coherent dynamics, and high densities with a conventional metallic phase. The results are relevant for recent tunneling and photoemission experiments in SrTiO3-based systems.
Article
Materials Science, Multidisciplinary
Ian Osborne, Thereza Paiva, Nandini Trivedi
Summary: By analyzing the single-particle spectral function for the Fermi Hubbard model, it was found that the Fermi surface undergoes a transition from a large Fermi surface to a smaller one near the Mott insulator. This non-Fermi liquid phase violates the Luttinger count and experiments have shown consistency with these numerical results.
Article
Physics, Nuclear
Rong Chen, Kevin E. Schmidt
Summary: This study presents a path-integral ground-state quantum Monte Carlo method for light nuclei in continuous space, demonstrating its efficiency in handling spin-isospin and spin-orbit interactions. The path-integral formulation allows straightforward calculation of operators that do not commute with the Hamiltonian, and Euclidean response functions, without the typical increase in variance seen in diffusion methods.
Article
Physics, Multidisciplinary
Tameem Albash, Conor Smith, Quinn Campbell, Andrew D. Baczewski
Summary: A parallel tempering method that trains multiple parameterized artificial neural networks independently is proposed to escape local minima in variational algorithms. The method incorporates an update step for exchange of neighboring ANN configurations and is demonstrated on two classes of Hamiltonians using Restricted Boltzmann Machines. It is shown to be useful in finding good approximations to ground states in cases where the standard training algorithm gets trapped in false minima.
Article
Physics, Multidisciplinary
Hao Xu, Hao Shi, Ettore Vitali, Mingpu Qin, Shiwei Zhang
Summary: This study determines the spin and charge orders in the doped 2D Hubbard model, mapping out the ground state phase diagram based on different doping and interaction strengths. The stripe order is found to be the ground state near 1/8 doping at strong interactions. Antiferromagnetic order persists from near half-filling to about 1/5 doping, with spin-density waves at lower interaction strengths or larger doping, and stripe states at stronger charge correlations.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Mathematics, Applied
Mrinal Sarkar
Summary: We numerically studied the Kuramoto model of identical oscillators arranged on a two-dimensional periodic square lattice and obtained the complete, nonequilibrium stationary-state phase diagram of the model. The dynamics of a single topological defect for various amplitudes and correlation time of the noise was also investigated, revealing that a finite correlation time promotes vortex excitations.
Article
Materials Science, Multidisciplinary
Owen Bradley, George G. Batrouni, Richard T. Scalettar
Summary: The Holstein Hamiltonian describes fermions interacting with phonons on a lattice. It predicts the behavior of dressed quasiparticles and the formation of superconducting and charge density wave phases at different densities. Quantum Monte Carlo calculations have been used to determine critical temperatures for these phase transitions in various lattice geometries.
Article
Physics, Fluids & Plasmas
Valentin Anfray, Christophe Chatelain
Summary: The random quantum q-state clock and Potts models are examined in two and three dimensions. The presence of Griffiths phases is investigated, and numerical evidence supports their existence in both models. The effects of finite-size and disorder strength are analyzed, and evidence suggests a shared critical behavior between the random quantum clock model and the Potts model.
Article
Chemistry, Physical
Alexander Schottelius, Francesco Mambretti, Anton Kalinin, Bjoern Beyersdorff, Andre Rothkirch, Claudia Goy, Jan Mueller, Nikolaos Petridis, Maurizio Ritzer, Florian Trinter, Jose M. Fernandez, Tiberio A. Ezquerra, Davide E. Galli, Robert E. Grisenti
Article
Physics, Multidisciplinary
Sebastiano Corli, Lorenzo Moro, Davide E. Galli, Enrico Prati
Summary: This study explores the Rubik's cube through a quantum formalism, representing it as a unitary representation of the Rubik's group, and revealing the behavior of cubies as bosons and fermions. By constructing Hamiltonian operators, it shows that the symmetries of the cube are preserved when the Hamiltonian is in its ground state. By utilizing deep reinforcement learning algorithm and Hamiltonian rewards, it successfully solves the Rubik's cube configurations.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Multidisciplinary Sciences
Akinobu Niozu, Yoshiaki Kumagai, Toshiyuki Nishiyama Hiraki, Hironobu Fukuzawa, Koji Motomura, Maximilian Bucher, Kazuki Asa, Yuhiro Sato, Yuta Ito, Daehyun You, Taishi Ono, Yiwen Li, Edwin Kukk, Catalin Miron, Liviu Neagu, Carlo Callegari, Michele Di Fraia, Giorgio Rossi, Davide Emilio Galli, Tommaso Pincelli, Alessandro Colombo, Shigeki Owada, Kensuke Tono, Takashi Kameshima, Yasumasa Joti, Tetsuo Katayama, Tadashi Togashi, Makina Yabashi, Kazuhiro Matsuda, Christoph Bostedt, Kiyoshi Ueda, Kiyonobu Nagaya
Summary: This study explores the formation process of solid Xe nanoparticles in an expanding supercooled Xe jet under vacuum conditions using X-ray diffraction experiments. It is found that the structure of Xe nanoparticles is a mixture of face-centered cubic and randomly stacked hexagonal close-packed structures, rather than pure face-centered cubic. Instantaneous coexistence of comparably sized face-centered cubic and hexagonal close-packed domains in single Xe nanoparticles is observed.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Physics, Multidisciplinary
Ettore Vitali, Peter Rosenberg, Shiwei Zhang
Summary: By leveraging cutting-edge numerical methodologies, this study investigates the ground state and properties of a two-dimensional spin-polarized Fermi gas in an optical lattice. The results provide strong evidence of the stability of the elusive Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superfluid phase, and show the existence of density order in the system, suggesting the possibility of an intricate coexistence of long-range orders in the ground state. The study also points out significant differences between the ground-state properties and the standard mean-field description, providing a compelling avenue for future theoretical and experimental explorations of spin imbalance, strong interactions, and superfluidity in this exotic phase of matter.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Marco Lazzarin, Davide Emilio Galli, Enrico Prati
Summary: Hybrid quantum-classical algorithms based on variational circuits are a promising approach for quantum machine learning problems. Tensor network-inspired circuits have been proposed as a natural choice, but their effectiveness on more difficult tasks is still unknown. This study presents experiments on multi-class classifiers and obtains encouraging results in image classification and quantum phase recognition.
Article
Multidisciplinary Sciences
Alessandro Carbone, Davide Emilio Galli, Mario Motta, Barbara Jones
Summary: This paper presents two strategies for the preparation of total spin eigenfunctions on quantum computers, and demonstrates the construction and implementation of these quantum circuits.
Article
Education, Scientific Disciplines
Annette Lopez, Patrick Kelly, Kaelyn Dauer, Ettore Vitali
Summary: This paper presents the key mechanisms behind superfluidity in fermionic systems and how to study neutron star superfluidity through simulating cold atomic Fermi gases. By introducing the concept of universality, the surprising similarity between cold atomic gases and neutron star superfluids is emphasized.
EUROPEAN JOURNAL OF PHYSICS
(2022)
Article
Multidisciplinary Sciences
F. Mambretti, M. Mirigliano, E. Tentori, N. Pedrani, G. Martini, P. Milani, D. E. Galli
Summary: Nanostructured Au films fabricated by assembling gas-phase nanoparticles exhibit non-linear and non-local electrical behavior, forming complex networks of metallic nanojunctions that continuously rearrange low and high electrical resistance regions due to thermal effects at the nanoscale. By developing a three-dimensional resistor network model, we are able to qualitatively reproduce the observed electrical conduction properties and extract information from the experimental resistance data. This suggests that nanostructured Au films have activated interconnections that can potentially be used for neuromorphic computing applications.
SCIENTIFIC REPORTS
(2022)
Article
Optics
Stefano Barison, Davide E. Galli, Mario Motta
Summary: The study explores the use of intrinsic atomic orbitals in quantum simulations of molecules to improve accuracy without increasing computational costs. By comparing different Ansatze, the ground-state energies and one-and two-body density operators are investigated, and the approach is demonstrated in calculating ground-and excited-state energies of small molecules using IBM quantum computers.
Article
Physics, Multidisciplinary
Hao Xu, Hao Shi, Ettore Vitali, Mingpu Qin, Shiwei Zhang
Summary: This study determines the spin and charge orders in the doped 2D Hubbard model, mapping out the ground state phase diagram based on different doping and interaction strengths. The stripe order is found to be the ground state near 1/8 doping at strong interactions. Antiferromagnetic order persists from near half-filling to about 1/5 doping, with spin-density waves at lower interaction strengths or larger doping, and stripe states at stronger charge correlations.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Martina Teruzzi, Christian Apostoli, Davide Pini, Davide Emilio Galli, Gianluca Bertaina
Summary: In this study, we focus on the clustering behavior of repulsive soft-core atomic systems at high densities, and investigate the transition from a Luttinger liquid to various cluster Luttinger liquids. The evolution of key observables related to density fluctuations exhibits a strong dependence on density, with the system displaying larger compressibility and rotonic excitations as density increases, ultimately leading to the clustering transition. Different theoretical approaches are compared for accuracy in different regimes, with the behavior described potentially observable in ultracold Rydberg-dressed gases.
Article
Physics, Fluids & Plasmas
F. Mambretti, M. Martinelli, F. Civillini, M. Bertoletti, S. Riva, N. Manini, D. E. Galli, D. Pini
Summary: In this study, we investigated the pairwise interactions of clusters consisting of two particles in two dimensions at a suitable density, using optimization techniques and Monte Carlo simulations. We found a second phase transition at extremely low temperature, leading from a high-temperature triangular dimer lattice with randomly disordered orientations to a low-temperature reduced-symmetry ground state with nematic orientational order and a slightly distorted structure.
Article
Optics
Ettore Vitali, Patrick Kelly, Annette Lopez, Gianluca Bertaina, Davide Emilio Galli
Article
Physics, Fluids & Plasmas
F. Mambretti, S. Molinelli, D. Pini, G. Bertaina, D. E. Galli
