scholarly journals Initialization of quantum simulators by sympathetic cooling

2020 ◽  
Vol 6 (10) ◽  
pp. eaaw9268 ◽  
Author(s):  
Meghana Raghunandan ◽  
Fabian Wolf ◽  
Christian Ospelkaus ◽  
Piet O. Schmidt ◽  
Hendrik Weimer
Keyword(s):  
Energy State ◽  
Hamiltonian Dynamics ◽  
Many Body ◽  
Sympathetic Cooling ◽  
Trapped Ion ◽  
Physical Chemical ◽  
Quantum Simulators ◽  
Auxiliary Particle ◽  
Quantum Simulator ◽  
Chemical And Biological Systems

Simulating computationally intractable many-body problems on a quantum simulator holds great potential to deliver insights into physical, chemical, and biological systems. While the implementation of Hamiltonian dynamics within a quantum simulator has already been demonstrated in many experiments, the problem of initialization of quantum simulators to a suitable quantum state has hitherto remained mostly unsolved. Here, we show that already a single dissipatively driven auxiliary particle can efficiently prepare the quantum simulator in a low-energy state of largely arbitrary Hamiltonians. We demonstrate the scalability of our approach and show that it is robust against unwanted sources of decoherence. While our initialization protocol is largely independent of the physical realization of the simulation device, we provide an implementation example for a trapped ion quantum simulator.

scholarly journals Probing Rényi entanglement entropy via randomized measurements

Science ◽  
2019 ◽  
Vol 364 (6437) ◽  
pp. 260-263 ◽  
Author(s):  
Tiff Brydges ◽  
Andreas Elben ◽  
Petar Jurcevic ◽  
Benoît Vermersch ◽  
Christine Maier ◽  
...  
Keyword(s):  
Quantum System ◽  
Entanglement Entropy ◽  
Quantum Systems ◽  
Quantum States ◽  
Many Body ◽  
Trapped Ion ◽  
Statistical Correlations ◽  
Quantum Simulator ◽  
Entanglement Structure ◽  
Arbitrary Quantum

Entanglement is a key feature of many-body quantum systems. Measuring the entropy of different partitions of a quantum system provides a way to probe its entanglement structure. Here, we present and experimentally demonstrate a protocol for measuring the second-order Rényi entropy based on statistical correlations between randomized measurements. Our experiments, carried out with a trapped-ion quantum simulator with partition sizes of up to 10 qubits, prove the overall coherent character of the system dynamics and reveal the growth of entanglement between its parts, in both the absence and presence of disorder. Our protocol represents a universal tool for probing and characterizing engineered quantum systems in the laboratory, which is applicable to arbitrary quantum states of up to several tens of qubits.

scholarly journals Practical verification protocols for analog quantum simulators

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Ryan Shaffer ◽  
Eli Megidish ◽  
Joseph Broz ◽  
Wei-Ting Chen ◽  
Hartmut Häffner
Keyword(s):  
System Size ◽  
Quantum Simulation ◽  
Quantum Devices ◽  
Error Sources ◽  
Trapped Ion ◽  
Quantum Simulators ◽  
Simulation Results ◽  
Quantum Simulator ◽  
Near Term ◽  
Significant Application

AbstractAnalog quantum simulation is expected to be a significant application of near-term quantum devices. Verification of these devices without comparison to known simulation results will be an important task as the system size grows beyond the regime that can be simulated classically. We introduce a set of experimentally-motivated verification protocols for analog quantum simulators, discussing their sensitivity to a variety of error sources and their scalability to larger system sizes. We demonstrate these protocols experimentally using a two-qubit trapped-ion analog quantum simulator and numerically using models of up to five qubits.

scholarly journals Many-Body Dephasing in a Trapped-Ion Quantum Simulator

2020 ◽  
Vol 125 (12) ◽  
Author(s):  
Harvey B. Kaplan ◽  
Lingzhen Guo ◽  
Wen Lin Tan ◽  
Arinjoy De ◽  
Florian Marquardt ◽  
...  
Keyword(s):  
Many Body ◽  
Trapped Ion ◽  
Quantum Simulator

scholarly journals Observation of a prethermal discrete time crystal

Science ◽  
2021 ◽  
Vol 372 (6547) ◽  
pp. 1192-1196
Author(s):  
A. Kyprianidis ◽  
F. Machado ◽  
W. Morong ◽  
P. Becker ◽  
K. S. Collins ◽  
...  
Keyword(s):  
Quantum System ◽  
Discrete Time ◽  
High Frequency ◽  
Statistical Physics ◽  
Time Window ◽  
General Strategy ◽  
Many Body ◽  
Trapped Ion ◽  
Quantum Simulator ◽  
Equilibrium Phases

Extending the framework of statistical physics to the nonequilibrium setting has led to the discovery of previously unidentified phases of matter, often catalyzed by periodic driving. However, preventing the runaway heating that is associated with driving a strongly interacting quantum system remains a challenge in the investigation of these newly discovered phases. In this work, we utilize a trapped-ion quantum simulator to observe the signatures of a nonequilibrium driven phase without disorder—the prethermal discrete time crystal. Here, the heating problem is circumvented not by disorder-induced many-body localization, but rather by high-frequency driving, which leads to an expansive time window where nonequilibrium phases can emerge. Floquet prethermalization is thus presented as a general strategy for creating, stabilizing, and studying intrinsically out-of-equilibrium phases of matter.

scholarly journals Quantum Chemistry Calculations on a Trapped-Ion Quantum Simulator

2018 ◽  
Vol 8 (3) ◽  
Author(s):  
Cornelius Hempel ◽  
Christine Maier ◽  
Jonathan Romero ◽  
Jarrod McClean ◽  
Thomas Monz ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Trapped Ion ◽  
Quantum Chemistry Calculations ◽  
Quantum Simulator

Experimental Realization of Multi-ion Sympathetic Cooling on a Trapped Ion Crystal

2021 ◽  
Vol 127 (14) ◽  
Author(s):  
Z.-C. Mao ◽  
Y.-Z. Xu ◽  
Q.-X. Mei ◽  
W.-D. Zhao ◽  
Y. Jiang ◽  
...  
Keyword(s):  
Sympathetic Cooling ◽  
Experimental Realization ◽  
Trapped Ion

THE DIFFERENTIAL GEOMETRY OF SCROLL WAVES

1991 ◽  
Vol 01 (04) ◽  
pp. 723-744 ◽  
Author(s):  
JOHN J. TYSON ◽  
STEVEN H. STROGATZ
Keyword(s):  
Traveling Waves ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Topological Constraint ◽  
Linking Number ◽  
Physical Chemical ◽  
Statics And Dynamics ◽  
Scroll Wave ◽  
Chemical And Biological Systems ◽  
Belousov Zhabotinskii Reaction

Traveling waves of excitation organize physical, chemical, and biological systems in space and time. In the biological context they serve to communicate information rapidly over long distances and to coordinate the activity of tissues and organs. An example of particular beauty, complexity and importance is the three-dimensional rotating scroll wave observed in the Belousov–Zhabotinskii reaction and in the ventricle of the heart. A scroll wave rotates around a filamentous phase singularity that weaves through the three-dimensional medium. At any instant of time the geometry of the scroll wave can be reduced to the spatial arrangement of a ribbon whose edges are the singular filament and the tip of the scroll wave. This ribbon, when it closes on itself, must satisfy the topological constraint L = Tw + Wr, where L is the linking number of the two edges of the ribbon, Tw is the total twist of the ribbon, and Wr is the writhing number of the singular filament. We discuss the origin of this equation and its implications for scroll wave statics and dynamics.

scholarly journals Dual-species, multi-qubit logic primitives for Ca+/Sr+ trapped-ion crystals

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
C. D. Bruzewicz ◽  
R. McConnell ◽  
J. Stuart ◽  
J. M. Sage ◽  
J. Chiaverini
Keyword(s):  
Quantum Logic ◽  
Near Infrared ◽  
Quantum Information Processing ◽  
Infrared Range ◽  
Sympathetic Cooling ◽  
Trapped Ion ◽  
Logic Control ◽  
State Transfer ◽  
And Control ◽  
Near Infrared Range

AbstractWe demonstrate key multi-qubit quantum-logic primitives in a dual-species trapped-ion system based on $${}^{40}$$40Ca$${}^{+}$$+ and $${}^{88}$$88Sr$${}^{+}$$+ ions, using two optical qubits with quantum-logic-control frequencies in the red to near-infrared range. With all ionization, cooling, and control wavelengths in a wavelength band similar for the two species and centered in the visible, and with a favorable mass ratio for sympathetic cooling, this pair is a promising candidate for scalable quantum information processing. Same-species and dual-species two-qubit gates, based on the Mølmer–Sørensen interaction and performed in a cryogenic surface-electrode trap, are characterized via the fidelity of generated entangled states; we achieve fidelities of 98.8(2)% and 97.5(2)% in Ca$${}^{+}$$+–Ca$${}^{+}$$+ and Sr$${}^{+}$$+–Sr$${}^{+}$$+ gates, respectively. For a similar Ca$${}^{+}$$+–Sr$${}^{+}$$+ gate, we achieve a fidelity of 94.3(3)%, and carrying out a Sr$${}^{+}$$+–Sr$${}^{+}$$+ gate performed with a Ca$${}^{+}$$+ sympathetic cooling ion in a Sr$${}^{+}$$+–Ca$${}^{+}$$+–Sr$${}^{+}$$+ crystal configuration, we achieve a fidelity of 95.7(3)%. These primitives form a set of trapped-ion capabilities for logic with sympathetic cooling and ancilla readout or state transfer for general quantum computing and communication applications.

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