PhD Student
Rydberg
Phone: 19481
braun@physi.uni-heidelberg.de
Physikalisches Institut
Universität Heidelberg
Im Neuenheimer Feld 226
69120, Heidelberg, Germany
Publications
2024
Geier S, Braemer A, Braun E, Müllenbach M, Franz T, Gärttner M, Zürn G, Weidemüller M
Time-reversal in a dipolar quantum many-body spin system Journal Article
In: Phys. Rev. Research, vol. 06, iss. 3, no. 033197, pp. 1-8, 2024.
@article{Geier2024,
title = {Time-reversal in a dipolar quantum many-body spin system},
author = {Sebastian Geier and Adrian Braemer and Eduard Braun and Maximilian Müllenbach and Titus Franz and Martin Gärttner and Gerhard Zürn and Matthias Weidemüller},
url = {https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.033197},
doi = {https://doi.org/10.1103/PhysRevResearch.6.033197},
year = {2024},
date = {2024-08-21},
urldate = {2024-08-21},
journal = {Phys. Rev. Research},
volume = {06},
number = {033197},
issue = {3},
pages = {1-8},
abstract = {Time reversal in a macroscopic system contradicts daily experience. It is practically impossible to restore a
shattered cup to its original state by just time reversing the microscopic dynamics that led to its breakage. Yet,
with the precise control capabilities provided by modern quantum technology, the unitary evolution of a quantum
system can be reversed in time. Here, we implement a time-reversal protocol in a dipolar interacting, isolated
many-body spin system represented by Rydberg states in an atomic gas. By changing the states encoding the
spin, we flip the sign of the interaction Hamiltonian, and demonstrate the reversal of the relaxation dynamics
of the magnetization by letting a demagnetized many-body state evolve back in time into a magnetized state.
We elucidate the role of atomic motion using the concept of a Loschmidt echo. Finally, by combining the
approach with Floquet engineering, we demonstrate time reversal for a large family of spin models with different
symmetries. Our method of state transfer is applicable across a wide range of quantum simulation platforms and
has applications far beyond quantum many-body physics, reaching from quantum-enhanced sensing to quantum
information scrambling.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Time reversal in a macroscopic system contradicts daily experience. It is practically impossible to restore a
shattered cup to its original state by just time reversing the microscopic dynamics that led to its breakage. Yet,
with the precise control capabilities provided by modern quantum technology, the unitary evolution of a quantum
system can be reversed in time. Here, we implement a time-reversal protocol in a dipolar interacting, isolated
many-body spin system represented by Rydberg states in an atomic gas. By changing the states encoding the
spin, we flip the sign of the interaction Hamiltonian, and demonstrate the reversal of the relaxation dynamics
of the magnetization by letting a demagnetized many-body state evolve back in time into a magnetized state.
We elucidate the role of atomic motion using the concept of a Loschmidt echo. Finally, by combining the
approach with Floquet engineering, we demonstrate time reversal for a large family of spin models with different
symmetries. Our method of state transfer is applicable across a wide range of quantum simulation platforms and
has applications far beyond quantum many-body physics, reaching from quantum-enhanced sensing to quantum
information scrambling.
shattered cup to its original state by just time reversing the microscopic dynamics that led to its breakage. Yet,
with the precise control capabilities provided by modern quantum technology, the unitary evolution of a quantum
system can be reversed in time. Here, we implement a time-reversal protocol in a dipolar interacting, isolated
many-body spin system represented by Rydberg states in an atomic gas. By changing the states encoding the
spin, we flip the sign of the interaction Hamiltonian, and demonstrate the reversal of the relaxation dynamics
of the magnetization by letting a demagnetized many-body state evolve back in time into a magnetized state.
We elucidate the role of atomic motion using the concept of a Loschmidt echo. Finally, by combining the
approach with Floquet engineering, we demonstrate time reversal for a large family of spin models with different
symmetries. Our method of state transfer is applicable across a wide range of quantum simulation platforms and
has applications far beyond quantum many-body physics, reaching from quantum-enhanced sensing to quantum
information scrambling.
Franz T, Geier S, Hainaut C, Braemer A, Thaicharoen N, Hornung M, Braun E, Gärttner M, Zürn G, Weidemüller M
Observation of anisotropy-independent magnetization dynamics in spatially disordered Heisenberg spin systems Journal Article
In: Phys. Rev. Research, vol. 06, iss. 3, no. 033131, pp. 1-12, 2024.
@article{Franz2024,
title = {Observation of anisotropy-independent magnetization dynamics in spatially disordered Heisenberg spin systems},
author = {Titus Franz and Sebastian Geier and Clément Hainaut and Adrian Braemer and Nithiwadee Thaicharoen and Moritz Hornung and Eduard Braun and Martin Gärttner and Gerhard Zürn and Matthias Weidemüller},
url = {https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.033131},
doi = {https://doi.org/10.1103/PhysRevResearch.6.033131},
year = {2024},
date = {2024-08-05},
urldate = {2024-08-05},
journal = {Phys. Rev. Research},
volume = {06},
number = {033131},
issue = {3},
pages = {1-12},
abstract = {An important step towards a comprehensive understanding of far-from-equilibrium dynamics of quantum
many-body systems is the identification of unifying features that are independent of microscopic details of the
system. We experimentally observe such robust features in the magnetization relaxation dynamics of disordered
Heisenberg XX, XXZ, and Ising Hamiltonians. We realize these Heisenberg spin models with tunable anisotropy
parameter and power-law interactions in an ensemble of Rydberg atoms by encoding the spin in suitable Rydberg
state combinations. We consistently observe stretched-exponential relaxation of magnetization for all considered
spin models, collapsing onto a single curve after appropriate rescaling of time. This robust short-time relaxation
behavior is explained by a perturbative treatment that exploits the strong disorder in pairwise couplings, which
leads to a description in terms of approximately independent pairs of spins. In numerical simulations of small
systems, we show that these pairs of spins constitute approximate local integrals of motion, which remain at least
partially conserved on a timescale exceeding the duration of the relaxation dynamics of the magnetization.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
An important step towards a comprehensive understanding of far-from-equilibrium dynamics of quantum
many-body systems is the identification of unifying features that are independent of microscopic details of the
system. We experimentally observe such robust features in the magnetization relaxation dynamics of disordered
Heisenberg XX, XXZ, and Ising Hamiltonians. We realize these Heisenberg spin models with tunable anisotropy
parameter and power-law interactions in an ensemble of Rydberg atoms by encoding the spin in suitable Rydberg
state combinations. We consistently observe stretched-exponential relaxation of magnetization for all considered
spin models, collapsing onto a single curve after appropriate rescaling of time. This robust short-time relaxation
behavior is explained by a perturbative treatment that exploits the strong disorder in pairwise couplings, which
leads to a description in terms of approximately independent pairs of spins. In numerical simulations of small
systems, we show that these pairs of spins constitute approximate local integrals of motion, which remain at least
partially conserved on a timescale exceeding the duration of the relaxation dynamics of the magnetization.
many-body systems is the identification of unifying features that are independent of microscopic details of the
system. We experimentally observe such robust features in the magnetization relaxation dynamics of disordered
Heisenberg XX, XXZ, and Ising Hamiltonians. We realize these Heisenberg spin models with tunable anisotropy
parameter and power-law interactions in an ensemble of Rydberg atoms by encoding the spin in suitable Rydberg
state combinations. We consistently observe stretched-exponential relaxation of magnetization for all considered
spin models, collapsing onto a single curve after appropriate rescaling of time. This robust short-time relaxation
behavior is explained by a perturbative treatment that exploits the strong disorder in pairwise couplings, which
leads to a description in terms of approximately independent pairs of spins. In numerical simulations of small
systems, we show that these pairs of spins constitute approximate local integrals of motion, which remain at least
partially conserved on a timescale exceeding the duration of the relaxation dynamics of the magnetization.