Article
Physics, Multidisciplinary
Wentao Chen, Yao Lu, Shuaining Zhang, Kuan Zhang, Guanhao Huang, Mu Qiao, Xiaolu Su, Jialiang Zhang, Jing-Ning Zhang, Leonardo Banchi, M. S. Kim, Kihwan Kim
Summary: A minimal-loss programmable phononic network is demonstrated, which can deterministically prepare and detect any phononic state. The network can be extended to reveal quantum advantage and has high reconstruction fidelities for both single- and two-phonon states.
Article
Multidisciplinary Sciences
Y. Z. He, C. G. Bao, Z. B. Li
Summary: This article studies the spin-textures of bound medium-body systems with spin-f atoms and explores the distribution of eigenstate energies under different spin states. The results show that the bottom-states are bipartite product states composed of fully polarized subsystems, while the top-states are paired product states influenced by different channel strengths.
SCIENTIFIC REPORTS
(2022)
Review
Physics, Multidisciplinary
C. Monroe, W. C. Campbell, L-M Duan, Z-X Gong, A. Gorshkov, P. W. Hess, R. Islam, K. Kim, N. M. Linke, G. Pagano, P. Richerme, C. Senko, N. Y. Yao
Summary: Laser-cooled and trapped atomic ions provide an ideal platform for simulating interacting quantum spin models. By using optical fields to modulate the ions' Coulomb interaction, long-range and tunable spin-spin interactions can be produced. This quantum simulator allows for the study of complex equilibrium states and dynamical processes in many-body interacting quantum systems.
REVIEWS OF MODERN PHYSICS
(2021)
Article
Physics, Multidisciplinary
J. Knoerzer, T. Shi, E. Demler, J. Cirac
Summary: By studying trapped-ion quantum systems, we can gain insights into generalized Holstein models and benchmark expensive numerical calculations. Our focus is on simulating many-electron systems and examining the competition between charge-density wave order, fermion pairing, and phase separation.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
J. D. Arias Espinoza, M. Mazzanti, K. Fouka, R. X. Schuessler, Z. Wu, P. Corboz, R. Gerritsma, A. Safavi-Naini
Summary: The proposed method uses optical tweezers to engineer the sound-wave spectrum of trapped ion crystals, allowing for tuning of interactions and connectivity beyond current setups. Demonstrated feasibility of generating target spin-spin interaction patterns in both one- and two-dimensional crystals using realistic tweezer settings and experimentally relevant trap parameters. This approach advances quantum simulation in trapped-ion platforms by enabling realization of a broader family of quantum spin Hamiltonians.
Article
Physics, Applied
Lijuan Dong, Inigo Arrazola, Xi Chen, Jorge Casanova
Summary: In this study, a pulsed dynamical decoupling technique using random or correlated pulse phases is incorporated to enhance the robustness of entangling spin-spin dynamics in trapped ions. Originally conceived for nuclear spin detection in nuclear magnetic resonance, this technique demonstrates applicability for robust quantum-information processing in trapped-ion settings.
PHYSICAL REVIEW APPLIED
(2021)
Article
Chemistry, Multidisciplinary
Jacob Whitlow, Zhubing Jia, Ye Wang, Chao Fang, Jungsang Kim, Kenneth R. Brown
Summary: This article presents a quantum simulation of conical intersections using a trapped atomic ion system, and experimentally observes the manifestation of geometric phase, demonstrating the advantage of combining spin and motion for quantum simulation of chemical reactions.
Article
Physics, Multidisciplinary
Daniel Carney, Hartmut Haffner, David C. Moore, Jacob M. Taylor
Summary: Electrons and ions trapped with electromagnetic fields, traditionally used as high-precision metrological instruments and quantum information processing platforms, can also serve as highly sensitive detectors for passing charged particles due to their extreme charge-to-mass ratio and low-noise quantum readout and control capabilities. These systems can detect energy depositions many orders of magnitude below typical ionization scales, showcasing potential applications in particle physics and noise characterization in quantum computers.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Holly N. Tinkey, Craig R. Clark, Brian C. Sawyer, Kenton R. Brown
Summary: In this study, we implemented a 2-qubit entangling interaction using a stationary, bichromatic optical beam within a surface-electrode Paul trap. We achieved a constant Doppler shift during the transport by fine temporal adjustment of the moving confinement potential. The interaction between the transported ions through the laser beam produced Bell states with fidelities comparable to those produced by stationary gates. This result demonstrates the feasibility of actively incorporating ion transport into quantum information entangling operations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Martin W. van Mourik, Pavel Hrmo, Lukas Gerster, Benjamin Wilhelm, Rainer Blatt, Philipp Schindler, Thomas Monz
Summary: This study investigates the energy dynamics of noncrystallized ions confined in a Paul trap. Numerical simulations were used to analyze rf heating and derive a simplified model of the energy dynamics. The model was experimentally confirmed, and the required parameters for efficient recrystallization were investigated.
Article
Chemistry, Physical
Oskar Asvany, Stephan Schlemmer
Summary: Rotational action spectroscopy is an experimental method used to record rotational spectra of molecules by action spectroscopy, rather than by detecting absorption of light by the molecules. Mainly applied to molecular ions, this method was initially limited by the low energy content of photons, but today there are various rotational action spectroscopic schemes available.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Optics
Mohamad Niknam, Robert N. Schwartz, Louis-S. Bouchard
Summary: We study quantum algorithmics with single spins and address technological challenges such as precision fabrication, rapid decoherence, atomic-scale addressing, and readout. By investigating fully polarized mesoscopic spin ensembles (spin-coherent states), we overcome atomic-scale challenges. In the limit where the ensembles are small compared to their separation, they can be treated as qubits with an effective coupling strength scaling with the number of spins. High-fidelity one- and two-qubit gate operations can be implemented if the spins within each ensemble are decoupled.
Article
Physics, Multidisciplinary
Martin Ringbauer, Michael Meth, Lukas Postler, Roman Stricker, Rainer Blatt, Philipp Schindler, Thomas Monz
Summary: Most quantum computers encode information in qubits using binary encoding, but the underlying physical hardware has a rich multilevel structure. We demonstrate a universal quantum processor using trapped ions that act as qudits with a high-dimensional Hilbert space.
Article
Physics, Multidisciplinary
Or Katz, Christopher Monroe
Summary: Trapped atomic ion crystals serve as a leading platform in quantum simulations of spin systems, where programmable and long-range spin-spin interactions are achieved through excitations of phonons. In this study, we propose a complementary approach using phonons in trapped-ion crystals to simulate bosonic systems, mediated by excitations of trapped-ion spins. This scheme allows for high programmability across a dense graph of bosonic couplings, utilizing long-lived collective phonon modes in a trapped-ion chain. It is well-suited for tackling challenging problems such as boson sampling and simulations of long-range bosonic and spin-boson Hamiltonians.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Wenbing Li, Sebastian Wolf, Lukas Klein, Dmitry Budker, Christoph E. Duellmann, Ferdinand Schmidt-Kaler
Summary: We demonstrate the implementation of three-dimensional polarization gradient cooling (PGC) for trapped ions. The cooling method is robust against an elevated phonon occupation number and works continuously in different cooling regimes. However, the performance of PGC strongly depends on residual micromotion and the spectral impurity of the laser field.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
Zhi-Yuan Wei, Daniel Malz, J. Ignacio Cirac
Summary: We introduce a class of states called plaquette projected entangled-pair states, which can be generated in a lattice by applying sequential unitaries to plaquettes of overlapping regions. They exhibit area-law entanglement, have long-range correlations, and generalize other tensor network states. We identify a more efficiently preparable subclass that can be prepared in a radial fashion and includes the family of isometric tensor network states. We also demonstrate the efficient preparation of this subclass using an array of photon sources.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
Alexander Luce, Ali Mahdavi, Florian Marquardt, Heribert Wankerl
Summary: This article introduces a Python package for calculating optical reflection and transmission in multilayer thin film structures, which provides fast parallel computation for experimentation with new optimization techniques, generation of datasets for machine learning, and effective evolutionary optimization. Additionally, an OpenAI Gym environment is provided for training reinforcement learning agents on the problem of finding multilayer thin-film configurations.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION
(2022)
Article
Physics, Multidisciplinary
Arthur Christianen, J. Ignacio Cirac, Richard Schmidt
Summary: In this study, the interaction between the polaron quasiparticle and chemical recombination in an atomic Bose-Einstein condensate (BEC) was investigated using a Gaussian state variational method. The results show that the polaron cloud contributes to the formation of bound states and leads to a shift of the Efimov resonance, indicating the onset of polaronic instability.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
J. Knoerzer, T. Shi, E. Demler, J. Cirac
Summary: By studying trapped-ion quantum systems, we can gain insights into generalized Holstein models and benchmark expensive numerical calculations. Our focus is on simulating many-electron systems and examining the competition between charge-density wave order, fermion pairing, and phase separation.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Juliane Doster, Tirth Shah, Thomas Foesel, Philipp Paulitschke, Florian Marquardt, Eva M. Weig
Summary: Nanomechanics has matured as a field, with coupled nanomechanical resonator arrays serving as important model systems for studying collective dynamics. In this study, a two-dimensional array of pillar resonators encoding a mechanical polarization degree of freedom was introduced to analyze polarization patterns and identify topological singularities.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Hengjiang Ren, Tirth Shah, Hannes Pfeifer, Christian Brendel, Vittorio Peano, Florian Marquardt, Oskar Painter
Summary: This article reports the realization of topological phonon transport in an optomechanical device and introduces the design and measurement results of the experiment. This study represents a significant advancement in the field of downscaled mechanical topological systems.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Rahul Trivedi, J. Ignacio Cirac
Summary: This study analyzes the complexity of continuous-time dynamics of locally interacting quantum spin systems with a constant rate of entanglement-breaking noise. It is proven that a polynomial time classical algorithm can be used to sample from the state of the spins when the rate of noise exceeds a certain threshold determined by the strength of the local interactions. Furthermore, by encoding a 1D fault-tolerant quantum computation into the dynamics of spin systems arranged on two or higher dimensional grids, it is shown that weakly simulating the output state of both purely Hamiltonian and purely dissipative dynamics is expected to be difficult in the low-noise regime.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Zongping Gong, Tommaso Guaita, J. Ignacio Cirac
Summary: In this paper, we study free fermions on lattices in arbitrary dimensions with hopping amplitudes that decay with a power-law. We provide a comprehensive set of constraints on the equilibrium and nonequilibrium properties of these fermions in the regime where the power-law decay is larger than the spatial dimension. Our results include the derivation of an optimal Lieb-Robinson bound and a clustering property for the Green's function. We also discuss the implications of these results on topological phases in long-range free-fermion systems.
PHYSICAL REVIEW LETTERS
(2023)
Review
Physics, Applied
Valentin Gebhart, Raffaele Santagati, Antonio Andrea Gentile, Erik M. Gauger, David Craig, Natalia Ares, Leonardo Banchi, Florian Marquardt, Luca Pezze, Cristian Bonato
Summary: Although the complexity of quantum systems increases exponentially with their size, classical algorithms and optimization strategies still play a crucial role in characterizing and detecting quantum states and dynamics. The future of quantum technologies relies on developing complex quantum systems for computation, simulation, and sensing, which poses challenges in control, calibration, and validation. This review explores classical post-processing techniques and adaptive optimization approaches to learn about quantum systems, their correlations, dynamics, and interaction with the environment, using various qubit architectures such as spin qubits, trapped ions, photonic and atomic systems, and superconducting circuits. It also highlights the importance of Bayesian formalism and neural networks.
NATURE REVIEWS PHYSICS
(2023)
Article
Computer Science, Artificial Intelligence
Alexander Luce, Ali Mahdavi, Heribert Wankerl, Florian Marquardt
Summary: In this research, the authors use a conditional invertible neural network (cINN) to design multilayer thin-films based on an optical target. The cINN is trained to learn the loss landscape of all thin-film configurations within a training dataset, allowing it to generate proposals for thin-film configurations that are close to the desired target. By further refining these proposals through local optimization, the generated thin-films achieve the target with greater precision compared to existing approaches. The cINN also demonstrates the ability to predict thin-films for out-of-distribution targets.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2023)
Article
Optics
Mario Krenn, Jonas Landgraf, Thomas Foesel, Florian Marquardt
Summary: In recent years, the rapid development in machine learning has had a significant impact on various fields of science and technology. This perspective article explores how quantum technologies are benefiting from this revolution. It showcases how scientists have utilized machine learning and artificial intelligence to analyze quantum measurements, estimate parameters of quantum devices, discover new quantum experimental setups and protocols, and improve aspects of quantum computing, communication, and simulation. The article also highlights the challenges and future possibilities in the field and provides speculative visions for the next decade.
Article
Materials Science, Multidisciplinary
Tirth Shah, Florian Marquardt, Vittorio Peano
Summary: The valley Hall effect is a useful method for creating stable waveguides for bosonic excitations such as photons and phonons. The absence of backscattering in many experiments is due to a smooth-envelope approximation that neglects large momentum transfer, but this accuracy is limited to small bulk band gaps and/or smooth domain walls. In experiments with larger bulk band gaps and hard domain walls, significant backscattering is expected. We demonstrate that in this relevant regime, the reflection of a wave at a sharp corner is highly sensitive to the orientation of the outgoing waveguide in relation to the underlying lattice. Enhanced backscattering occurs due to resonant tunneling transitions in quasimomentum space. Tracking the resonant tunneling energies with changes in waveguide orientation reveals a self-repeating fractal pattern that is also observed in the density of states and the backscattering rate at a sharp corner.
Article
Quantum Science & Technology
Riccardo Porotti, Antoine Essig, Benjamin Huard, Florian Marquardt
Summary: Quantum control has gained increasing interest recently, and feedback-based deep reinforcement learning strategies hold great promise for solving quantum control problems. This study found that reinforcement learning can successfully discover feedback strategies, achieving high-fidelity state preparation and even superposition states.
Article
Quantum Science & Technology
Naeimeh Mohseni, Thomas Foesel, Lingzhen Guo, Carlos Navarrete-Benlloch, Florian Marquardt
Summary: The study demonstrates the power of deep learning in predicting the dynamics of quantum many-body systems, even without full information during training, accurately predicting driving trajectories. This scheme provides considerable speedup for pulse optimization.
Article
Materials Science, Multidisciplinary
Lingzhen Guo, Vittorio Peano, Florian Marquardt
Summary: Recent research has discovered that atoms subjected to a time-periodic drive can form a crystal structure in phase space. The interactions between atoms lead to collective phonon excitations and phononic Chern insulator in the phase space crystal, accompanied by topologically robust chiral transport. This finding has important implications for the dynamics of two-dimensional charged particles in a strong magnetic field.
