33 research outputs found
Probing many-body dynamics on a 51-atom quantum simulator
Controllable, coherent many-body systems can provide insights into the
fundamental properties of quantum matter, enable the realization of new quantum
phases and could ultimately lead to computational systems that outperform
existing computers based on classical approaches. Here we demonstrate a method
for creating controlled many-body quantum matter that combines
deterministically prepared, reconfigurable arrays of individually trapped cold
atoms with strong, coherent interactions enabled by excitation to Rydberg
states. We realize a programmable Ising-type quantum spin model with tunable
interactions and system sizes of up to 51 qubits. Within this model, we observe
phase transitions into spatially ordered states that break various discrete
symmetries, verify the high-fidelity preparation of these states and
investigate the dynamics across the phase transition in large arrays of atoms.
In particular, we observe robust manybody dynamics corresponding to persistent
oscillations of the order after a rapid quantum quench that results from a
sudden transition across the phase boundary. Our method provides a way of
exploring many-body phenomena on a programmable quantum simulator and could
enable realizations of new quantum algorithms.Comment: 17 pages, 13 figure
Industry applications of neutral-atom quantum computing solving independent set problems
Architectures for quantum computing based on neutral atoms have risen to
prominence as candidates for both near and long-term applications. These
devices are particularly well suited to solve independent set problems, as the
combinatorial constraints can be naturally encoded in the low-energy Hilbert
space due to the Rydberg blockade mechanism. Here, we approach this connection
with a focus on a particular device architecture and explore the ubiquity and
utility of independent set problems by providing examples of real-world
applications. After a pedagogical introduction of basic graph theory concepts
of relevance, we briefly discuss how to encode independent set problems in
Rydberg Hamiltonians. We then outline the major classes of independent set
problems and include associated example applications with industry and social
relevance. We determine a wide range of sectors that could benefit from
efficient solutions of independent set problems -- from telecommunications and
logistics to finance and strategic planning -- and display some general
strategies for efficient problem encoding and implementation on neutral-atom
platforms.Comment: 28 pages, 9 example application
Cold Matter Assembled Atom-by-Atom
The realization of large-scale fully controllable quantum systems is an
exciting frontier in modern physical science. We use atom-by-atom assembly to
implement a novel platform for the deterministic preparation of regular arrays
of individually controlled cold atoms. In our approach, a measurement and
feedback procedure eliminates the entropy associated with probabilistic trap
occupation and results in defect-free arrays of over 50 atoms in less than 400
ms. The technique is based on fast, real-time control of 100 optical tweezers,
which we use to arrange atoms in desired geometric patterns and to maintain
these configurations by replacing lost atoms with surplus atoms from a
reservoir. This bottom-up approach enables controlled engineering of scalable
many-body systems for quantum information processing, quantum simulations, and
precision measurements.Comment: 12 pages, 9 figures, 3 movies as ancillary file
Integrating Neural Networks with a Quantum Simulator for State Reconstruction
We demonstrate quantum many-body state reconstruction from experimental data
generated by a programmable quantum simulator, by means of a neural network
model incorporating known experimental errors. Specifically, we extract
restricted Boltzmann machine (RBM) wavefunctions from data produced by a
Rydberg quantum simulator with eight and nine atoms in a single measurement
basis, and apply a novel regularization technique to mitigate the effects of
measurement errors in the training data. Reconstructions of modest complexity
are able to capture one- and two-body observables not accessible to
experimentalists, as well as more sophisticated observables such as the R\'enyi
mutual information. Our results open the door to integration of machine
learning architectures with intermediate-scale quantum hardware.Comment: 15 pages, 13 figure
Quantum Kibble-Zurek mechanism and critical dynamics on a programmable Rydberg simulator
Quantum phase transitions (QPTs) involve transformations between different
states of matter that are driven by quantum fluctuations. These fluctuations
play a dominant role in the quantum critical region surrounding the transition
point, where the dynamics are governed by the universal properties associated
with the QPT. While time-dependent phenomena associated with classical,
thermally driven phase transitions have been extensively studied in systems
ranging from the early universe to Bose Einstein Condensates, understanding
critical real-time dynamics in isolated, non-equilibrium quantum systems is an
outstanding challenge. Here, we use a Rydberg atom quantum simulator with
programmable interactions to study the quantum critical dynamics associated
with several distinct QPTs. By studying the growth of spatial correlations
while crossing the QPT, we experimentally verify the quantum Kibble-Zurek
mechanism (QKZM) for an Ising-type QPT, explore scaling universality, and
observe corrections beyond QKZM predictions. This approach is subsequently used
to measure the critical exponents associated with chiral clock models,
providing new insights into exotic systems that have not been understood
previously, and opening the door for precision studies of critical phenomena,
simulations of lattice gauge theories and applications to quantum optimization
Atom-by-atom assembly of defect-free one-dimensional cold atom arrays
The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a platform for the deterministic preparation of regular one-dimensional arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 milliseconds. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach may enable controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements
Aquila: QuEra's 256-qubit neutral-atom quantum computer
The neutral-atom quantum computer "Aquila" is QuEra's latest device available
through the Braket cloud service on Amazon Web Services (AWS). Aquila is a
"field-programmable qubit array" (FPQA) operated as an analog Hamiltonian
simulator on a user-configurable architecture, executing programmable coherent
quantum dynamics on up to 256 neutral-atom qubits. This whitepaper serves as an
overview of Aquila and its capabilities: how it works under the hood, key
performance benchmarks, and examples that demonstrate some quintessential
applications. This includes an overview of neutral-atom quantum computing, as
well as five examples of increasing complexity from single-qubit dynamics to
combinatorial optimization, implemented on Aquila. This whitepaper is intended
for readers who are interested in learning more about neutral-atom quantum
computing, as a guide for those who are ready to start using Aquila, and as a
reference point for its performance as an analog quantum computer
A quantum processor based on coherent transport of entangled atom arrays
The ability to engineer parallel, programmable operations between desired
qubits within a quantum processor is central for building scalable quantum
information systems. In most state-of-the-art approaches, qubits interact
locally, constrained by the connectivity associated with their fixed spatial
layout. Here, we demonstrate a quantum processor with dynamic, nonlocal
connectivity, in which entangled qubits are coherently transported in a highly
parallel manner across two spatial dimensions, in between layers of single- and
two-qubit operations. Our approach makes use of neutral atom arrays trapped and
transported by optical tweezers; hyperfine states are used for robust quantum
information storage, and excitation into Rydberg states is used for
entanglement generation. We use this architecture to realize programmable
generation of entangled graph states such as cluster states and a 7-qubit
Steane code state. Furthermore, we shuttle entangled ancilla arrays to realize
a surface code with 19 qubits and a toric code state on a torus with 24 qubits.
Finally, we use this architecture to realize a hybrid analog-digital evolution
and employ it for measuring entanglement entropy in quantum simulations,
experimentally observing non-monotonic entanglement dynamics associated with
quantum many-body scars. Realizing a long-standing goal, these results pave the
way toward scalable quantum processing and enable new applications ranging from
simulation to metrology.Comment: 23 pages, 14 figures; movie attached as ancillary fil