Article
Materials Science, Multidisciplinary
Zhipeng Sun
Summary: The Fermi surface topology plays a crucial role in the study of high-temperature superconductivity cuprates. The conventional method for determining the Fermi surface is not always reliable due to its sensitivity to noise or precision issues. In this study, a simple and specific notion, the derivative of the momentum distribution function with respect to the chemical potential, is proposed as a reliable approach to determine the Fermi surface.
Article
Materials Science, Multidisciplinary
J. H. Nyhegn, G. M. Bruun, K. Knakkergaard Nielsen
Summary: A nonperturbative scheme for calculating the wave function of magnetic polarons in a bilayer antiferromagnet is developed, providing insights into their spatial properties and dressing cloud structure.
Article
Multidisciplinary Sciences
Joannis Koepsell, Dominik Bourgund, Pimonpan Sompet, Sarah Hirthe, Annabelle Bohrdt, Yao Wang, Fabian Grusdt, Eugene Demler, Guillaume Salomon, Christian Gross, Immanuel Bloch
Summary: The research reveals the competition between antiferromagnetism and hole motion in two-dimensional Mott insulators, as well as the transition from an anomalous metal to a conventional Fermi liquid with varying doping levels. Using a cold-atom quantum simulator, the transformation of multipoint correlations between spins and holes is observed to change with increasing doping, with the crossover completed around 30% hole doping. This work provides insights into theoretical approaches and potential connections to lower-temperature phenomena.
Article
Physics, Multidisciplinary
M. Hachmann, Y. Kiefer, J. Riebesehl, R. Eichberger, A. Hemmerich
Summary: In this study, spin-polarized samples and spin mixtures of quantum degenerate fermionic atoms are prepared in selected excited Bloch bands of an optical checkerboard square lattice. The extreme band lifetimes above 10 s for the spin-polarized case reflect the suppression of collisions by Pauli's exclusion principle. The remarkable large values of about 1 s found for spin mixtures demonstrate the basis for exploring the physics of Fermi gases with two paired spin components in orbital optical lattices, including the regime of unitarity.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
K. Knakkergaard Nielsen, T. Pohl, G. M. Bruun
Summary: This study develops a nonperturbative theory to describe the dynamics of holes in antiferromagnetic spin lattices, using thet-Jmodel. By generalizing the self-consistent Born approximation to non-equilibrium systems, the full time-dependent many-body wave function can be calculated. The study reveals three distinct dynamical regimes, leading to the formation of magnetic polarons.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Xinyang Dong, Emanuel Gull, Andrew J. Millis
Summary: This study investigates the contribution of electron-spin-fluctuation coupling to the superconducting state in a two-dimensional Hubbard model using the dynamical cluster approximation. The findings suggest that only about half of the superconductivity can be attributed to the pairing mechanism involving spin fluctuations as pairing bosons in the standard one-loop theory.
Article
Optics
Cheng Peng, Ruijin Liu, Wei Zhang, Xiaoling Cui
Summary: In this study, the physics of Fermi polarons and molecules have been explored using a unified variational Ansatz, confirming the existence of a first-order transition in 3D and 2D Fermi polarons. The nature of this transition is determined by an energy competition between systems with different momenta. Additionally, different variational methods have been used to study the nature of the polaron-molecule transition in 2D systems, with consistent conclusions reached.
Article
Physics, Multidisciplinary
Julius de Hond, Jinggang Xiang, Woo Chang Chung, Enid Cruz-Colon, Wenlan Chen, William Cody Burton, Colin J. Kennedy, Wolfgang Ketterle
Summary: This study examines a special ground state of bosons with two spin states in an optical lattice - the spinMott insulator. This state is composed of repulsively bound pairs and is insulating for both spin and charge transport. One of the decay regimes observed exhibits protection by the pairing gap.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Luhang Yang, Ignacio Hamad, Luis O. Manuel, Adrian E. Feiguin
Summary: This study presents a numerical investigation of competing orders in the 1D t-J model with long-range RKKY-like staggered spin interactions. By circumventing the constraints of Mermin-Wagner's theorem, this model can exhibit long-range Neel order at half filling. The full phase diagram as a function of exchange and particle density is determined using the density matrix renormalization group (DMRG) method. It is found that pairing is discouraged, and the AFM insulator and metallic phases are separated by a broad phase segregation region. The effects of phase separation re-emerge at low densities. Upon doping, interactions induce a confining potential that binds holons and spinons into fermionic quasiparticles. The photoemission spectrum of the model is numerically calculated, revealing the appearance of a coherent quasiparticle band with a width determined by J that survives at finite doping. Comparison with analytical results and the spinon-holon problem provide insights into the internal structure of the quasiparticles and explain the different features in the spectrum. The study also discusses the implications of this simple toy model for the phenomenology of higher-dimensional counterparts.
Article
Materials Science, Multidisciplinary
Petar Cubela, Annabelle Bohrdt, Markus Greiner, Fabian Grusdt
Summary: It is unclear how effective low-energy degrees of freedom and the corresponding field theories emerge from microscopic models in doped antiferromagnets. This study demonstrates the existence of various long-lived excitations in a doped one-dimensional spin chain in a staggered magnetic field, including magnons, mesonic pairs, and tetraparton bound states. The introduction of a strong-coupling theory allows for the analysis of the polaronic dressing and molecular binding of mesons to collective magnon excitations. The experimental realization of this system can be achieved in quantum gas microscopes.
Article
Materials Science, Multidisciplinary
Chuan Chen, Inti Sodemann, Patrick A. Lee
Summary: The study explores the model of correlated electrons coupled with itinerant metallic electrons, examining the competition between spin liquid states and interlayer coherent heavy metallic states. The results suggest that weak interlayer tunneling can destroy the spin liquid state, leading to the emergence of Kondo metallic states or Fermi liquid transitions.
Article
Materials Science, Multidisciplinary
Ruipeng Li, Jonas von Milczewski, Atac Imamoglu, Rafal Oldziejewski, Richard Schmidt
Summary: We study induced pairing between two identical fermions mediated by an attractively interacting quantum impurity in two-dimensional systems. Based on a stochastic variational method (SVM), we investigate the influence of confinement and finite interaction range on the ground state of the quantum three-body problem. We find that confinement and a finite interaction range can enhance trimer stability and overcome Coulomb repulsion, opening possibilities for electron pairing beyond conventional paradigms.
Article
Materials Science, Multidisciplinary
Ansgar Schubert, Christian B. Mendl
Summary: This paper derives higher-order error bounds with small prefactors for a general Trotter product formula, generalizing a result given by Childs et al. [Phys. Rev. X 11, 011020 (2021)]. The bounds are then applied to the real-time quantum time evolution operator governed by the Fermi-Hubbard Hamiltonian on one-dimensional and two-dimensional square and triangular lattices. The main technical contribution of the work is a symbolic evaluation of nested commutators between hopping and interaction terms for a given lattice geometry. However, comparison with the actual Trotter error (evaluated on a small system) shows that the bounds still overestimate the error.
Article
Multidisciplinary Sciences
Zhuoyu Chen, Yao Wang, Slavko N. Rebec, Tao Jia, Makoto Hashimoto, Donghui Lu, Brian Moritz, Robert G. Moore, Thomas P. Devereaux, Zhi-Xun Shen
Summary: The synthesis and spectroscopic analysis of the 1D cuprate Ba2-xSrxCuO3+delta over a wide range of hole doping was reported. Angle-resolved photoemission experiments revealed the doping evolution of the holon and spinon branches. An additional strong near-neighbor attraction, possibly arising from coupling to phonons, quantitatively explained the experiments for all accessible doping levels. Consideration of structural and quantum chemistry similarities among cuprates suggests that this attraction may also play a crucial role in high-temperature cuprate superconductors.
Article
Optics
Esben Rohan Christensen, Arturo Camacho-Guardian, Georg M. Bruun
Summary: This study explores the properties of a mobile ion immersed in a quantum degenerate gas of fermionic atoms, revealing distinct characteristics of ionic Fermi polarons compared to neutral polaron. Ionic polarons exhibit multiple stable states and smooth transitions from repulsive to attractive with increasing interaction strength. Interestingly, the residue of the ionic polaron increases with Fermi density, which contrasts with the behavior of neutral polarons.
Article
Multidisciplinary Sciences
Pimonpan Sompet, Sarah Hirthe, Dominik Bourgund, Thomas Chalopin, Julian Bibo, Joannis Koepsell, Petar Bojovic, Ruben Verresen, Frank Pollmann, Guillaume Salomon, Christian Gross, Timon A. Hilker, Immanuel Bloch
Summary: Topology has revolutionized our understanding of quantum phases in many-body systems. In this study, a finite-temperature version of a topological Haldane phase is achieved using a quantum simulator based on ultracold atoms. The characteristics of the system, both at the edges and in the bulk, are directly revealed through measurements and correlation functions. The robustness of the phase to charge fluctuations far from the regime of the Heisenberg model is investigated by varying the Hubbard interaction strength.
Article
Physics, Multidisciplinary
Annabelle Bohrdt, Lukas Homeier, Immanuel Bloch, Eugene Demler, Fabian Grusdt
Summary: Studies suggest that high-temperature pairing of fermions can be achieved in bilayer models, utilizing the energy gained by one charge when it follows the path created by another charge.
Article
Physics, Multidisciplinary
S. Mistakidis, G. M. Koutentakis, F. Grusdt, P. Schmelcher, H. R. Sadeghpour
Summary: In this study, we investigate the formation and phase diagram of magnetic Bose polaron in a one-dimensional spinor Bose gas. The residue of magnetic polarons decreases significantly with strong impurity-spin interactions. Impurities can be utilized to manipulate spin polarization and suppress spin-spin correlations in the magnetic medium.
NEW JOURNAL OF PHYSICS
(2022)
Article
Chemistry, Physical
Roman Bause, Arthur Christianen, Andreas Schindewolf, Immanuel Bloch, Xin-Yu Luo
Summary: In ultracold collisions involving bialkali molecules, long-lived complexes can result in unexpected two-body loss in samples of nonreactive molecules.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Multidisciplinary Sciences
Xing-Yan Chen, Andreas Schindewolf, Sebastian Eppelt, Roman Bause, Marcel Duda, Shrestha Biswas, Tijs Karman, Timon Hilker, Immanuel Bloch, Xin-Yu Luo
Summary: Scattering resonances are a useful tool for controlling interactions of ultracold atoms and molecules. Conventional Feshbach scattering resonances are not expected to exist in most ultracold polar molecules due to fast loss during close approach. However, a new type of scattering resonance, called field-linked resonances, has been demonstrated to be universal for a wide range of polar molecules. These resonances provide a tuning knob for independently controlling elastic contact interaction and dipole-dipole interaction, leading to potential applications in dipolar superfluids and molecular supersolids.
Article
Multidisciplinary Sciences
Sarah Hirthe, Thomas Chalopin, Dominik Bourgund, Petar Bojovic, Annabelle Bohrdt, Eugene Demler, Fabian Grusdt, Immanuel Bloch, Timon A. Hilker
Summary: In this study, the experimental method of quantum gas of ultracold atoms was used to observe hole pairing phenomenon caused by magnetic correlations in a doped antiferromagnetic ladder system with mixed-dimensional couplings. The results showed that magnetic correlations can significantly increase the binding energy of holes and reduce the pair size, allowing holes to predominantly occupy the same rung of the ladder. It was also found that spatial structures in the pair distribution appeared with increased doping, indicating repulsion between bound hole pairs. By engineering a configuration to enhance binding, a strategy to increase the critical temperature for superconductivity was outlined.
Article
Physics, Multidisciplinary
F. A. Palm, M. Kurttutan, A. Bohrdt, U. Schollwoeck, F. Grusdt
Summary: Strongly interacting fermionic systems can exhibit interesting quantum many-body states with exotic excitations. This study focuses on the interplay between strong interactions and the Pauli exclusion principle in the Hofstadter-Fermi-Hubbard model. The researchers discover a lattice analog of the quantum Hall ferromagnet at magnetic filling factor nu = 1, and observe spin-singlet states with spin-spin correlations similar to skyrmions. They also predict the breakdown of flat-band ferromagnetism at large fields. This work opens up possibilities for experimental studies of lattice QH ferromagnetism and its relation to high-Tc superconductivity.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Multidisciplinary
Kritsana Srakaew, Pascal Weckesser, Simon Hollerith, David Wei, Daniel Adler, Immanuel Bloch, Johannes Zeiher
Summary: Coherent control of the collective optical properties of an array of quantum emitters can be achieved by driving a single ancilla atom to a Rydberg state. This allows for spatial control over the optical response and enhances light-matter coupling at the level of single quanta. These results represent progress towards realizing quantum coherent metasurfaces, controlled atom-photon entanglement, and deterministic engineering of quantum states of light.
Article
Physics, Multidisciplinary
Marcel Duda, Xing-Yan Chen, Andreas Schindewolf, Roman Bause, Jonas von Milczewski, Richard Schmidt, Immanuel Bloch, Xin-Yu Luo
Summary: The interplay of quantum statistics and interactions in atomic Bose-Fermi mixtures results in a phase transition from a polaronic to a molecular phase, leading to the emergence of a molecular Fermi gas. This represents a new phenomenon complementary to the Bose-Einstein condensate/Bardeen-Cooper-Schrieffer crossover observed in Fermi systems. By tuning interspecies interactions, heteronuclear molecules can be generated in the quantum-degenerate regime.
Article
Multidisciplinary Sciences
Lena H. Dogra, Gevorg Martirosyan, Timon A. Hilker, Jake A. P. Glidden, Jiri Etrych, Alec Cao, Christoph Eigen, Robert P. Smith, Zoran Hadzibabic
Summary: Boyle's observation in 1662 that the volume of a gas is inversely proportional to pressure at constant temperature is now a cornerstone of equilibrium thermodynamics. In this study, we experimentally construct an equation of state for a turbulent cascade of matter waves in a homogeneous ultracold atomic Bose gas. We show that the amplitude of the momentum distribution and the underlying energy flux can serve as equilibrium-like state variables, related by an equation of state that does not depend on the details of energy injection or dissipation, or on the system's history. Furthermore, we find that the equations of state for a wide range of interaction strengths and gas densities can be empirically scaled onto each other, resulting in a universal dimensionless equation of state.
Article
Physics, Multidisciplinary
Henning Schloemer, Annabelle Bohrdt, Lode Pollet, Ulrich Schollwoeck, Fabian Grusdt
Summary: This study uses the density matrix renormalization group method at finite temperature to analyze the formation of stripes in the mixed-dimensional t-J model. It is found that a stable vertical stripe phase can be formed in the absence of pairing, exhibiting incommensurate magnetic order and long-range charge density wave profiles. The proposed model can be seen as a parent Hamiltonian of the stripe phase, and its hidden spin correlations contribute to the predicted resilience against quantum and thermal fluctuations.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Julius Dicke, Lukas Rammelmueller, Fabian Grusdt, Lode Pollet
Summary: We investigate the phase diagram of two different mixed-dimensional t-Jz-J1 models on the square lattice, with hopping amplitude t only nonzero along the x direction. In the first bosonic model, the spin-exchange amplitude J1 is negative and isotropic along the x and y directions, with isotropic and positive Jz. The low-energy physics is characterized by spin-charge separation. In the second model, J1 is restricted to the x axis while Jz remains isotropic and positive. The model exhibits stripe patterns with antiferromagnetic Neel order at low temperature and high hole densities.
Article
Chemistry, Physical
Roman Bause, Arthur Christianen, Andreas Schindewolf, Immanuel Bloch, Xin-Yu Luo
Summary: Collisional complexes formed in ultracold collisions involving bialkali molecules can live for milliseconds and cause unexpected two-body loss in nonreactive molecular samples, significantly impacting the preparation of dense and stable molecular samples.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Materials Science, Multidisciplinary
Petar Cubela, Annabelle Bohrdt, Markus Greiner, Fabian Grusdt
Summary: It is unclear how effective low-energy degrees of freedom and the corresponding field theories emerge from microscopic models in doped antiferromagnets. This study demonstrates the existence of various long-lived excitations in a doped one-dimensional spin chain in a staggered magnetic field, including magnons, mesonic pairs, and tetraparton bound states. The introduction of a strong-coupling theory allows for the analysis of the polaronic dressing and molecular binding of mesons to collective magnon excitations. The experimental realization of this system can be achieved in quantum gas microscopes.