Degree of Quantumness in Quantum Synchronization

Quantum parallelism can be implemented on a classical ensemble of discrete level quantum systems. The nano systems are not quite identical and the ensemble represents their individual variability. An underlying Lie algebraic theory is developed using the closure of the algebra to demonstrate the parallel information processing at the level of the ensemble. The ensemble is addressed by a sequence of laser pulses. In the Heisenberg picture of quantum dynamics the coherence between the N levels of a given quantum system can be handled as an observable. Thereby there are N2 logic variables per N level system. This is how massive parallelism is achieved in that there are N2 potential outputs for a quantum system of N levels. The use of an ensemble allows simultaneous reading of such outputs. Due to size dispersion the expectation values of the observables can differ somewhat from system to system. We show that for a moderate variability of the systems one can average the N2 expectation values over the ensemble while retaining closure and parallelism. This allows directly propagating in time the ensemble averaged values of the observables. Results of simulations of electronic excitonic dynamics in an ensemble of quantum dot, QD, dimers are presented. The QD size and interdot distance in the dimer are used to parametrize the Hamiltonian. The dimer N levels include local and charge transfer excitons within each dimer. The well-studied physics of semi-conducting QDs suggests that the dimer coherences can be probed at room temperature

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Massively Parallel Classical Logic via Coherent Dynamics of an Ensemble of Quantum Systems with Dispersion in Size

10.26434/chemrxiv.12370538.v1 ◽

2020 ◽

Cited By ~ 4

Author(s):

Hugo Gattuso ◽

Raphael D. Levine ◽

Francoise Remacle

Keyword(s):

Quantum System ◽

Quantum Dynamics ◽

Algebraic Theory ◽

Laser Pulses ◽

Quantum Systems ◽

Individual Variability ◽

Expectation Values ◽

Charge Transfer Excitons ◽

Simultaneous Reading ◽

Size Dispersion

Quantum parallelism can be implemented on a classical ensemble of discrete level quantum systems. The nano systems are not quite identical and the ensemble represents their individual variability. An underlying Lie algebraic theory is developed using the closure of the algebra to demonstrate the parallel information processing at the level of the ensemble. The ensemble is addressed by a sequence of laser pulses. In the Heisenberg picture of quantum dynamics the coherence between the N levels of a given quantum system can be handled as an observable. Thereby there are N2 logic variables per N level system. This is how massive parallelism is achieved in that there are N2 potential outputs for a quantum system of N levels. The use of an ensemble allows simultaneous reading of such outputs. Due to size dispersion the expectation values of the observables can differ somewhat from system to system. We show that for a moderate variability of the systems one can average the N2 expectation values over the ensemble while retaining closure and parallelism. This allows directly propagating in time the ensemble averaged values of the observables. Results of simulations of electronic excitonic dynamics in an ensemble of quantum dot, QD, dimers are presented. The QD size and interdot distance in the dimer are used to parametrize the Hamiltonian. The dimer N levels include local and charge transfer excitons within each dimer. The well-studied physics of semi-conducting QDs suggests that the dimer coherences can be probed at room temperature

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Transferring Quantum Information in Hybrid Quantum Systems Consisting of a Quantum System with Limited Control and a Quantum Computer

Quantum Science and Technology - Hybrid Quantum Systems ◽

10.1007/978-981-16-6679-7_14 ◽

2021 ◽

pp. 315-347

Author(s):

Ryosuke Sakai ◽

Akihito Soeda ◽

Mio Murao

Keyword(s):

Quantum Information ◽

Quantum System ◽

Quantum Computer ◽

Quantum Systems ◽

Hybrid Quantum Systems

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Massively parallel classical logic via coherent dynamics of an ensemble of quantum systems with dispersion in size

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2008170117 ◽

2020 ◽

Vol 117 (35) ◽

pp. 21022-21030 ◽

Cited By ~ 2

Author(s):

Hugo Gattuso ◽

R. D. Levine ◽

F. Remacle

Keyword(s):

Quantum System ◽

Quantum Dynamics ◽

Algebraic Theory ◽

Laser Pulses ◽

Quantum Systems ◽

Individual Variability ◽

Expectation Values ◽

Charge Transfer Excitons ◽

Simultaneous Reading ◽

Size Dispersion

Quantum parallelism can be implemented on a classical ensemble of discrete level quantum systems. The nanosystems are not quite identical, and the ensemble represents their individual variability. An underlying Lie algebraic theory is developed using the closure of the algebra to demonstrate the parallel information processing at the level of the ensemble. The ensemble is addressed by a sequence of laser pulses. In the Heisenberg picture of quantum dynamics the coherence between theNlevels of a given quantum system can be handled as an observable. Thereby there areN2logic variables perNlevel system. This is how massive parallelism is achieved in that there areN2potential outputs for a quantum system ofNlevels. The use of an ensemble allows simultaneous reading of such outputs. Due to size dispersion the expectation values of the observables can differ somewhat from system to system. We show that for a moderate variability of the systems one can average theN2expectation values over the ensemble while retaining closure and parallelism. This allows directly propagating in time the ensemble averaged values of the observables. Results of simulations of electronic excitonic dynamics in an ensemble of quantum dot (QD) dimers are presented. The QD size and interdot distance in the dimer are used to parametrize the Hamiltonian. The dimerNlevels include local and charge transfer excitons within each dimer. The well-studied physics of semiconducting QDs suggests that the dimer coherences can be probed at room temperature.

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Quantum Characterization, Verification, and Validation

Oxford Research Encyclopedia of Physics ◽

10.1093/acrefore/9780190871994.013.38 ◽

2018 ◽

Author(s):

Joel Wallman ◽

Steven Flammia ◽

Ian Hincks

Keyword(s):

Information Processing ◽

Quantum Information ◽

Quantum System ◽

Fault Tolerant ◽

Scale Up ◽

Quantum Algorithm ◽

Quantum Systems ◽

Verification And Validation ◽

Forthcoming Article ◽

Prime Factorization

This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Physics. Please check back later for the full article. Quantum systems may outperform current digital technologies at various information processing tasks, such as simulating the dynamics of quantum systems and integer factorization. Quantum Characterization, Verification, and Validation (QCVV) is the procedure for estimating the quality of physical quantum systems for use as information processors. QCVV consists of three components. Characterization means determining the effect of control operations on a quantum system, and the nature of external noise acting on the quantum system. The first characterization experiments (Rabi, Ramsey, and Hahn-echo) were developed in the context of nuclear magnetic resonance. As other effective two-level systems with varying noise models have been identified and couplings become more complex, additional techniques such as tomography and randomized benchmarking have been developed specifically for quantum information processing. Verification involves verifying that a control operation implements a desired ideal operation to within a specified precision. Often, these targets are set by the requirements for quantum error correction and fault-tolerant quantum computation in specific architectures. Validation is demonstrating that a quantum information processor can solve specific problems. For problems whose solution can be efficiently verified (e.g., prime factorization), validation may involve running a corresponding quantum algorithm (e.g., Shor’s algorithm) and analyzing the time taken to produce the correct solution. For problems whose solution cannot be efficiently verified, for example, quantum simulation, developing adequate techniques is an active area of research. The essential features that make a device useful as a quantum information processor also create difficulties for QCVV, and specialized techniques have been developed to surmount these difficulties. The field is now entering a mature phase where a broad range of techniques can address all three tasks. As quantum information processors continue to scale up and improve, these three tasks look to become increasingly relevant, and many challenges remain.

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