Article
Physics, Multidisciplinary
Jing Yang, Adolfo del Campo
Summary: The exchange operator formalism is used to describe many-body integrable systems in terms of phase-space variables. We establish an equivalence between models described by this formalism and the infinite family of parent Hamiltonians describing quantum many-body models with Jastrow form ground states. This allows us to identify the invariants of motion and establish integrability for any model in the family.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Mitchell J. Knight, Harry M. Quiney, Andy M. Martin
Summary: This paper describes the variational determination of the two-fermion reduced density matrix for harmonically trapped, ultracold few-fermion systems in one dimension with equal spin populations. The problem is formulated as a semi-definite program subject to N-representability conditions. The ground-state energies, density, pair-correlation function, and eigenvalues of the 2-RDM are found using an augmented Lagrangian method. The results show that this method accurately describes the salient features of the systems and has the potential to handle larger systems.
NEW JOURNAL OF PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Wei Tang, Jutho Haegeman
Summary: This paper investigates the microscopic construction of Kac-Moody algebra in continuous systems and validates it through bosonization and Bethe ansatz methods. The computation of Kac-Moody generators is also tested using continuous matrix product state simulations.
Article
Mechanics
Tribikram Gupta, Kalpana Sharma, M. Lavanyaa, Sanjay Gupta
Summary: Graphene nanoribbons (GNRs) are widely used in nanoelectronics and opto-electronics. In this study, we investigated the energy spectrum and mapping of alternate bond systems in one-dimensional and quasi one-dimensional chains. Our findings provide valuable insights for the applications of GNRs.
Article
Materials Science, Multidisciplinary
G. Salerno, T. Ozawa, P. Torma
Summary: This study investigates the effect of quantum geometry on the many-body ground state of one-dimensional interacting bosonic systems. The researchers find that the Drude weight is determined by the sum of the kinetic energy and a term proportional to the many-body quantum metric. Importantly, the many-body quantum metric sets the upper bound for the Drude weight. The results are validated using exact diagonalization on the Creutz ladder model. This work sheds light on the significance of many-body quantum geometry in one-dimensional interacting bosonic systems.
Article
Optics
Yabo Li, Dominik Schneble, Tzu-Chieh Wei
Summary: We investigate dynamically coupled one-dimensional Bose-Hubbard models and solve for the wave functions and energies of two-particle eigenstates. Our study reveals the existence of four different continua and three doublon dispersions in the two-particle spectrum of a system with generic interactions. The presence of doublons and their energies depend on the coupling strength between two species of bosons and the interaction strengths. We provide details on the spectrum and properties of two-particle states, and analyze the difference in time evolution under different coupling strengths and the relation between the long-time behavior of the system and the doublon dispersion. These dynamics can be observed in cold atoms and potentially simulated by digital quantum computers.
Article
Optics
Aoi Hayashi, Suman Mondal, Tapan Mishra, B. P. Das
Summary: In a one-dimensional dimerized optical lattice, the extended Bose-Hubbard model shows stable density-wave (DW) and bond-order density-wave (BODW) phases at specific fillings and lattice dimerizations. The BODW phase is more robust with stronger hopping dimerization, and a phase crossover occurs with varying nearest-neighbor interaction. The stability of the BODW phase is further examined in the presence of finite on-site interactions.
Article
Optics
Maciej Lebek, Andrzej Syrwid, Piotr T. Grochowski, Kazimierz Rzazewski
Summary: We analyze the dynamics of one-dimensional quantum gases with strongly attractive contact interactions and find that attractive forces can effectively act as strongly repulsive ones. Our findings extend the theoretical results on the super-Tonks-Girardeau gas and have implications for the domain stability in a two-component Fermi gas. We also discuss the effects of finite-range interactions and analyze the universality of the presented results. Moreover, our conclusions support the existence of metastable quantum droplets in the regime of strongly attractive contact and attractive dipolar interactions.
Article
Optics
Dmitry Kouznetsov, Pol Van Dorpe, Niels Verellen
Summary: This paper catalogs known optical moire lattices and discovers exotic lattice configurations using a geometric analog of the Eratosthenes algorithm. Numerical simulations of time-of-flight interference patterns reveal the rich dynamics of Bose-Einstein condensates loaded into these optical lattices. The unique feature of this method is the ability to tune the periodicity of the lattices without changing the laser wavelength, while maintaining the local potential at each lattice site.
Article
Physics, Multidisciplinary
Madhumita Sarkar, Mainak Pal, Arnab Sen, Krishnendu Sengupta
Summary: We numerically analyze spin-1/2 fermions in a one-dimensional harmonic potential with a magnetic point-like impurity. Even for a few particles, we observe ground state level crossings between different fermion parities. We interpret this as a few-body precursor to a quantum phase transition, where the impurity breaks a Cooper pair. This interpretation is supported by analyzing density-density correlations in momentum space. Finally, we discuss the experimental realization of the system using existing cold-atom platforms.
Article
Physics, Multidisciplinary
Tran Duong Anh-Tai, Mathias Mikkelsen, Thomas Busch, Thomas Fogarty
Summary: We systematically study the emergence of quantum chaos in a minimal system of one-dimensional harmonically trapped Bose-Bose mixtures by tuning the particle-particle interactions. Using improved exact diagonalization scheme, we show that one can obtain strong signatures of chaos by increasing the inter-component interaction strength and breaking the symmetry of intra-component interactions.
Article
Optics
Zoran Ristivojevic
Summary: We study the polaron quasiparticle in a one-dimensional Bose gas using the Yang-Gaudin model, deriving an exact result for the polaron mass in the thermodynamic limit. The polaron mass is expressed in terms of the derivative with respect to the density of the ground-state energy per particle of the Bose gas without the polaron, allowing for high-order power series calculations in weak and strong interaction regimes.
Article
Physics, Multidisciplinary
Asmi Haldar, Krishnanand Mallayya, Markus Heyl, Frank Pollmann, Marcos Rigol, Arnab Das
Summary: Quantum phase transitions are important for understanding the distinct properties exhibited by matter at very low temperatures upon small changes in microscopic parameters. Locating these transitions accurately is challenging, but a new method involving sudden quenches to force systems out of equilibrium shows promise. The transitions leave distinctive features in intermediate-time dynamics and equilibrated local observables, with effective temperature showing minima near quantum critical points. Further research will focus on testing these results in experiments with Rydberg atoms and exploring nonequilibrium signatures of quantum critical points in models with topological transitions.
Article
Mathematics, Interdisciplinary Applications
Xiuye Liu, Jianhua Zeng
Summary: In this study, the formation, properties, and dynamics of matter-wave structures in one-dimensional LHY quantum fluids are analyzed and numerically simulated. The findings are significant for quantum-gas experiments, providing new insights into low-dimensional LHY physics.
CHAOS SOLITONS & FRACTALS
(2022)
Article
Physics, Multidisciplinary
Yijian Zou, Karthik Siva, Tomohiro Soejima, Roger S. K. Mong, Michael P. Zaletel
Summary: This study introduces two related non-negative measures of tripartite entanglement and shows that states with nonzero measures have nontrivial entanglement. Additionally, it demonstrates that these entanglement measures in one dimension depend only on the emergent low-energy theory. For a gapped system, it argues that entanglement measures either both nonzero or both zero, depending on the system's ground state. Furthermore, a numerical algorithm is developed for computing entanglement measures in critical systems.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Applied
E. Bahnsen, S. E. Rasmussen, N. J. S. Loft, N. T. Zinner
Summary: As the application of quantum technology approaches, leveraging current quantum resources becomes crucial. Utilizing the diamond gate instead of standard gates has shown to be more efficient in compiling quantum algorithms. These gates can be decomposed into standard gates and have a wide range of applications in quantum machine learning.
PHYSICAL REVIEW APPLIED
(2022)
Article
Physics, Multidisciplinary
Maciej Lewenstein, David Cirauqui, Miguel Angel Garcia-March, Guillem Guigo Corominas, Przemyslaw Grzybowski, Jose R. M. Saavedra, Martin Wilkens, Jan Wehr
Summary: The study revisited the approach to the Edwards-Anderson model by evaluating and analyzing the probability distribution of configurations of two replicas of the system, generating squares of thermal copies of spin variables from the two copies of the systems.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Editorial Material
Physics, Multidisciplinary
Carlo Manzo, Gorka Munoz-Gil, Giovanni Volpe, Miguel Angel Garcia-March, Maciej Lewenstein, Ralf Metzler
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2023)
Article
Physics, Multidisciplinary
Nicolas Firbas, Oscar Garibo-i-Orts, Miguel Angel Garcia-March, J. Alberto Conejero
Summary: The results of the AnDi Challenge demonstrate the superior performance of machine learning methods, particularly recurrent neural networks (RNNs), in characterizing anomalous diffusion. A new architecture called ConvTransformer, combining convolutional and transformer networks, is proposed to extract features from diffusive trajectories. This approach achieves improved performance in determining the underlying diffusive regime, especially in short trajectories, which is crucial for experimental researchers.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2023)
Article
Physics, Condensed Matter
Sergi De Maria-Garcia, Albert Ferrando, J. Alberto Conejero, Pedro Fernandez De Cordoba, Miguel Angel Garcia-March
Summary: We propose a method for studying the dynamics of a quasi-two dimensional Bose-Einstein condensate with vortices at arbitrary locations. The method provides an analytical solution for the condensate's dynamics in a homogeneous medium and in a parabolic trap, assuming ideal non-interacting conditions. It also allows for predicting the merging time of vortices in the condensate by obtaining algebraic equations for the trajectories of phase singularities. Additionally, we adapt the method from photonics to Bose-Einstein condensates and extend it to trapped systems for the first time, and present numerical simulations considering nonlinear cases.
Article
Quantum Science & Technology
Frederik Kofoed Marqversen, Nikolaj Thomas Zinner
Summary: We discuss the procedure for obtaining measurement-based implementations of quantum algorithms given by quantum circuit diagrams and how to reduce the required resources needed for a given measurement-based computation. This forms the foundation for quantum computing on photonic systems in the near term. To demonstrate that these ideas are well grounded we present three different problems which are solved by employing a measurement-based implementation of the variational quantum eigensolver algorithm (MBVQE). We show that by utilising native measurement-based gates rather than standard gates, such as the standard controlled not gate (CNOT), measurement-based quantum computations may be obtained that are both shallow and have simple connectivity while simultaneously exhibiting a large expressibility. We conclude that MBVQE has promising prospects for resource states that are not far from what is already available today.
QUANTUM SCIENCE AND TECHNOLOGY
(2023)
Article
Optics
Lasse Bjorn Kristensen, Morten Kjaergaard, Christian Kraglund Andersen, Nikolaj Thomas Zinner
Summary: This research presents a hybrid approach combining autonomous correction and traditional measurement-based quantum error correction to correct the dominant phase and decay errors in superconducting qubit architectures. Numerical simulations demonstrate that this scheme can significantly increase the storage time by five to ten times and requires only six qubits for encoding and two ancillary qubits for autonomous correction, leading to a substantial reduction in qubit overhead compared to typical measurement-based error-correction schemes. Furthermore, this scheme can be implemented in a wide range of architectures as it relies on standard interactions and qubit driving available in most major quantum computing platforms.
Article
Chemistry, Multidisciplinary
Marco Majland, Rasmus Berg Jensen, Mads Greisen Hojlund, Nikolaj Thomas Zinner, Ove Christiansen
Summary: The excessive measurement overheads in estimating physical quantities hinder the demonstration of practical quantum advantages for near-term devices. However, the reduction in resource requirements for computing anharmonic, vibrational states remains unexplored compared to its electronic counterpart. Through the manipulation of vibrational systems, such as employing coordinate transformations, we can significantly reduce the number of measurements needed to estimate anharmonic, vibrational states.
Article
Materials Science, Multidisciplinary
A. Alnor, T. Baekkegaard, N. T. Zinner
Summary: Different topological phases of quantum systems have been a focus of research in recent decades. This study goes beyond typical spin-1/2 systems and explores the realization of higher Chern numbers and the emergence of different topological phases using spin-1 systems. The results show that rich topological phase diagrams can be achieved through numerical and analytical methods, and the realistic implementation of spin-1 systems in superconducting circuits holds promise for experimental verification of these theoretical predictions.
Article
Optics
S. E. Rasmussen, N. T. Zinner
Summary: In this paper, the entangling quantum generative adversarial network (EQ-GAN) is investigated for multiqubit learning. It is shown that EQ-GAN can learn circuits more efficiently than SWAP test and generate excellent overlap matrix elements for learning VQE states of small molecules. However, the lack of phase estimation prevents it from directly estimating energy. Additionally, EQ-GAN demonstrates its potential in learning random states.
Article
Physics, Fluids & Plasmas
Kasper Poulsen, Nikolaj T. Zinner
Summary: Heat and noise control are crucial for the development of quantum technologies. Heat rectifiers, which allow for one-way heat transport, are powerful tools for this purpose. We propose a rectifier based on the unidirectionality of a low temperature bath, which can block heat transport in one configuration but allow it in the other.
Article
Physics, Nuclear
Tomasz Sowinski, Miguel A. Garcia-March
Summary: In this work, the authors discuss the limitations of the eigenvalue continuation approach when applied to strongly correlated many-body systems. By using a simple system and model, they demonstrate that the eigenvector continuation is unable to surpass the accuracy of the sampling states. They propose the need for support from other complementary methods to overcome this inaccuracy.
Article
Physics, Multidisciplinary
Muhammad Miskeen Khan, Mohammad Mehboudi, Hugo Tercas, Maciej Lewenstein, Miguel Angel Garcia-March
Summary: We propose experimentally feasible means for nondestructive thermometry of homogeneous Bose-Einstein condensates in different spatial dimensions (d is an element of {1 , 2, 3}). Our impurity-based protocol suggests that the fundamental error bound on thermometry at the subnanokelvin domain depends highly on the dimension, in that the higher the dimension the better the precision. Furthermore, suboptimal thermometry of the condensates by using measurements that are experimentally feasible is explored. We specifically focus on measuring position and momentum of the impurity that belong to the family of Gaussian measurements. We show that, generally, experimentally feasible measurements are far from optimal, except in one dimension, where position measurements are indeed optimal. This makes realistic experiments perform very well at few nanokelvin temperatures for all dimensions, and at subnanokelvin temperatures in the one-dimensional scenario. These results take a significant step towards experimental realization of probe-based quantum thermometry of Bose-Einstein condensates, as it deals with them in one, two, and three dimensions and uses feasible measurements applicable in current experimental setups.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Optics
Kasper Poulsen, Alan C. Santos, Lasse B. Kristensen, Nikolaj T. Zinner
Summary: This study introduces a class of quantum rectifiers that can improve performance by utilizing quantum entanglement. By coupling two small spin chains through a double-slit interface, rectification can be significantly enhanced, even in small systems, and the effect can withstand noisy environments.
Article
Physics, Fluids & Plasmas
Kasper Poulsen, Marco Majland, Seth Lloyd, Morten Kjaergaard, Nikolaj T. Zinner
Summary: Maxwell's demon is a quintessential example of information control necessary for designing quantum devices. Our study demonstrates that non-Markovian effects can be exploited to optimize the information transfer rate in quantum Maxwell demons.
