Instrumentation for quantum computers

Ambiguity int he contact between laboratory instruments and equations of quantum mechanics is formulated in terms of responses of the instruments to commands transmitted to them by a Classical digital Process-control Computer (CPC); in this way instruments are distinguished from quantum- mechanical models (sets of equations) that specify what is desired of the instruments. Results include: (1) a formulation of quantum mechanics adapted to computer- controlled instruments; (2) a lower bound on the precision of unitary transforms required for quantum searching and a lower bound on sample size needed to show that instruments implement a desired model at that precision; (3) a lower bound on precision of timing required of a CPC in directing instruments; (4) a demonstration that guesswork is necessary in ratcheting up the precision of commands.Ambiguity int he contact between laboratory instruments and equations of quantum mechanics is formulated in terms of responses of the instruments to commands transmitted to them by a Classical digital Process-control Computer (CPC); in this way instruments are distinguished from quantum- mechanical models (sets of equations) that specify what is desired of the instruments. Results include: (1) a formulation of quantum mechanics adapted to computer- controlled instruments; (2) a lower bound on the precision of unitary transforms required for quantum searching and a lower bound on sample size needed to show that instruments implement a desired model at that precision; (3) a lower bound on precision of timing required of a CPC in directing instruments; (4) a demonstration that guesswork is necessary in ratcheting up the precision of commands.

arXiv:quant-ph/0005007Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEJul 13, 20001 citation

Experimental Aspects of Quantum Computing

Henry O. Everitt

Springer eBooksJan 1, 200538 citations

Stochastic errors in quantum instruments

Darian McLaren, Matthew A. Graydon, Joel J. Wallman

Fault-tolerant quantum computation requires non-destructive quantum measurements with classical feed-forward. Many experimental groups are actively working towards implementing such capabilities and so they need to be accurately evaluated. As with unitary channels, an arbitrary imperfect implementation of a quantum instrument is difficult to analyze. In this paper, we define a class of quantum instruments that correspond to stochastic errors and thus are amenable to standard analysis methods. We derive efficiently computable upper- and lower-bounds on the diamond distance between two quantum instruments. Furthermore, we show that, for the special case of uniform stochastic instruments, the diamond distance and the natural generalization of the process infidelity to quantum instruments coincide and are equal to a well-defined probability of an error occurring during the measurement.Fault-tolerant quantum computation requires non-destructive quantum measurements with classical feed-forward. Many experimental groups are actively working towards implementing such capabilities and so they need to be accurately evaluated. As with unitary channels, an arbitrary imperfect implementation of a quantum instrument is difficult to analyze. In this paper, we define a class of quantum instruments that correspond to stochastic errors and thus are amenable to standard analysis methods. We derive efficiently computable upper- and lower-bounds on the diamond distance between two quantum instruments. Furthermore, we show that, for the special case of uniform stochastic instruments, the diamond distance and the natural generalization of the process infidelity to quantum instruments coincide and are equal to a well-defined probability of an error occurring during the measurement.

arXiv:2306.07418Jun 12, 20230 citations

International Conference on Quantum Technologies for High-Energy Physics (QT4HEP22)

Moritz Kirste

Quantum Computers rely on classical instrumentation to control the quantum processing unit. In 2018, Zurich Instruments introduced the first commercial Quantum Computing Control System (QCCS), designed to control more than 100 superconducting and spin qubits. In this talk, I will introduce the basic instrumentation required to operate a quantum computer and present our collaborative approach with leading research partners to pioneer quantum advantage from the control electronics side.Quantum Computers rely on classical instrumentation to control the quantum processing unit. In 2018, Zurich Instruments introduced the first commercial Quantum Computing Control System (QCCS), designed to control more than 100 superconducting and spin qubits. In this talk, I will introduce the basic instrumentation required to operate a quantum computer and present our collaborative approach with leading research partners to pioneer quantum advantage from the control electronics side.

Jan 1, 20220 citations

The quantum instrument monad

Tobias Fritz

Monads are a ubiquitous structure in functional programming used for modelling computational effects. For example, the state monad models the effect of a computation interacting with a memory system. Here we introduce the quantum instrument monad $\mathcal{I}_\mathcal{A}$ , which models the effect of a computation interacting with a quantum system with algebra of observables $\mathcal{A}$ . It can be thought of as a noncommutative generalization of the state monad. We construct this quantum instrument monad in two versions: a finitary version on the category of sets and a measure-theoretic version on the category of measurable spaces (the latter under the assumption that $\mathcal{A}$ is a type I von Neumann algebra with separable predual). Both versions are strong monads. The construction of the measure-theoretic version is based on a new notion of integral of a quantum-operation-valued function against a state-valued measure.Monads are a ubiquitous structure in functional programming used for modelling computational effects. For example, the state monad models the effect of a computation interacting with a memory system. Here we introduce the quantum instrument monad $\mathcal{I}_\mathcal{A}$, which models the effect of a computation interacting with a quantum system with algebra of observables $\mathcal{A}$. It can be thought of as a noncommutative generalization of the state monad. We construct this quantum instrument monad in two versions: a finitary version on the category of sets and a measure-theoretic version on the category of measurable spaces (the latter under the assumption that $\mathcal{A}$ is a type I von Neumann algebra with separable predual). Both versions are strong monads. The construction of the measure-theoretic version is based on a new notion of integral of a quantum-operation-valued function against a state-valued measure.

cs.LOCross-listedarXiv:2606.27805Jun 29, 20260 citations

\mathcal{I}_\mathcal{A}

, which models the effect of a computation interacting with a quantum system with algebra of observables

\mathcal{A}

. It can be thought of as a noncommutative generalization of the state monad. We construct this quantum instrument monad in two versions: a finitary version on the category of sets and a measure-theoretic version on the category of measurable spaces (the latter under the assumption that

\mathcal{A}

is a type I von Neumann algebra with separable predual). Both versions are strong monads. The construction of the measure-theoretic version is based on a new notion of integral of a quantum-operation-valued function against a state-valued measure.