Most Recent Preprints
Observation of magnon bound states in the long-range, anisotropic Heisenberg model
arXiv:2212.03899
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Over the recent years coherent, time-periodic modulation has been established as a versatile tool for realizing novel Hamiltonians. Using this approach, known as Floquet engineering, we experimentally realize a long-ranged, anisotropic Heisenberg model with tunable interactions in a trapped ion quantum simulator. We demonstrate that the spectrum of the model contains not only single magnon excitations but also composite magnon bound states. For the long-range interactions with the experimentally realized power-law exponent, the group velocity of magnons is unbounded. Nonetheless, for sufficiently strong interactions we observe bound states of these unconventional magnons which possess a non-diverging group velocity. By measuring the configurational mutual information between two disjoint intervals, we demonstrate the implications of the bound state formation on the entanglement dynamics of the system. Our observations provide key insights into the peculiar role of composite excitations in the non-equilibrium dynamics of quantum many-body systems.
Quantum Theory of Light Interaction with a Dielectric Sphere: Towards 3D Ground-State Cooling
arXiv:2212.04838
Entanglement phase diagrams from partial transpose moments
arXiv:2212.10181
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More Preprints
We present experimentally and numerically accessible quantities that can be used to differentiate among various families of random entangled states. To this end, we analyze the entanglement properties of bipartite reduced states of a tripartite pure state. We introduce a ratio of simple polynomials of low-order moments of the partially transposed reduced density matrix and show that this ratio takes well-defined values in the thermodynamic limit for various families of entangled states. This allows to sharply distinguish entanglement phases, in a way that can be understood from a quantum information perspective based on the spectrum of the partially transposed density matrix. We analyze in particular the entanglement phase diagram of Haar random states, states resulting form the evolution of chaotic Hamiltonians, stabilizer states, which are outputs of Clifford circuits, Matrix Product States, and fermionic Gaussian states. We show that for Haar random states the resulting phase diagram resembles the one obtained via the negativity and that for all the cases mentioned above a very distinctive behaviour is observed. Our results can be used to experimentally test necessary conditions for different types of mixed-state randomness, in quantum states formed in quantum computers and programmable quantum simulators.
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Research Groups
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The research group led by Rainer Blatt investigates quantum processes in a system of few ions held in ion traps. The experiments aim at achieving complete control over all quantum degrees of freedom in...
Quantum Optics and Spectroscopy -
The research team led by Francesca Ferlaino focuses on the study of dipolar quantum phenomena, using strongly magnetic atomic species. In 2012, the group has created the first Bose-Einstein...
Dipolar Quantum Gases -
The research group led by R. GRIMM investigates ultracold particle systems consisting of optically trapped quantum gases at temperatures close to absolute zero. Because of their superb experimental...
Ultracold Atoms and Quantum Gases -
Gerhard Kirchmair’s research group works on superconducting circuits and their application for quantum computation and simulation. Superconducting Josephson junctions are used to realize the quantum...
Superconducting quantum circuits -
The research group led by Hannes Pichler studies quantum optical systems, quantum many-body physics and quantum information. The group aims at laying the theoretical foundations for next generation...
Many-Body Quantum Optics -
The research group led by Oriol Romero-Isart studies topics in the fields of theoretical quantum optics and quantum nanophysics in the context of quantum science and technology. One of the main...
Quantum Nanophysics, Optics and Information -
Wittgenstein awardee Peter Zoller’s research group studies topics in the fields of theoretical quantum optics and atomic physics as well as quantum information and condensed matter theory. The...
Quantum Optics