US 2026/0228596 A1Published application

Method for implementing a quantum measurement

AssigneeAlgorithmiq Oy

InventorAdam Glos

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Abstract

The present invention is related to a method for implementing a quantum measurement on a system quantum state of a composite system of a quantum computing device, said composite system comprising a plurality of quantum mechanical subsystems Qn, n=1 N, N≥2, said quantum mechanical subsystems being preferably qubits, and said quantum computing device having a connectivity and operativity that allows to implement for each of said subsystems Qn a potentially imperfect realization of a joint unitary operation (I) and a joint quantum measurement on a joint system of said subsystem Qn and at least one connected subsystem (II), of said plurality of subsystems, said realization of said joint quantum measurement being described by a plurality of measurement operators (III) each measurement operator (III) being associated with a measurement outcome (IV). The present invention is further related to an apparatus for carrying out said method.

Claims18

Dependent claims

A method for implementing a quantum measurement on a system quantum state of a composite system of a quantum computing device, said composite system comprising a plurality of quantum mechanical subsystems Qn, n=1, . . . , N, N≥2, said quantum mechanical subsystems being preferably qubits, and said quantum computing device having a connectivity and operativity that allows to implement for each of said subsystems Qn a potentially imperfect realization of a joint unitary operation Un,nc and a joint quantum measurement on a joint system of said subsystem Qn and at least one connected subsystem Qnc of said plurality of subsystems, said realization of said joint quantum measurement being described by a plurality of measurement operators MMn,ncN,N,c, each measurement operator

M
m
n
,
n
c
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n
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n
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being associated with a measurement outcome mn,nc,
wherein said method comprises:
an initial measurement step which comprises for at least one initially selected subsystem Qn0 a realization of an n0-th local Positive Operator Valued Measure on said initially selected subsystem Qn0 to thereby obtain a measurement outcome mn0;
an iterative measurement step which comprises for at least one iteratively selected subsystem Qn a realization of an n-th local Positive Operator Valued Measure on said iteratively selected subsystem Qn by implementing, by operation of said quantum computing device, said potentially imperfect realization of said joint unitary operation Un,nc followed by said joint quantum measurement described by said plurality of measurement operators
M
m
n
,
n
c
(
n
,
n
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on said joint system of said iteratively selected subsystem Qn and said at least one connected subsystem Qnc, wherein said at least one connected subsystem Qnc is in a previously determined quantum state described by a density operator on ρnc, to thereby obtain a measurement outcome mn,nc,
wherein for at least one iteratively selected subsystem Qn at least one of said connected subsystems Qnc, and each of said connected subsystems Qnc, is one of said at least one initially selected subsystems Qno.

27 more elements

A quantum computing device said quantum computing device comprising a composite system comprising a plurality of quantum mechanical subsystems Qn, n=1, . . . , N, N≥2, said quantum mechanical subsystems being qubits, and said quantum computing device having a connectivity and operativity that allows to implement for each of said subsystems Qn a potentially imperfect realization of a joint unitary operation Un,nc and a joint quantum measurement on a joint system of said subsystem Qn and at least one connected subsystem Qnc of said plurality of subsystems, said realization of said joint quantum measurement being described by a plurality of measurement operators

M
m
n
,
n
c
(
n
,
n
c
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,
being associated with a measurement each measurement operator
M
m
n
,
n
c
(
n
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bring associated with a measurement outcome mn,nc,
said quantum computing device further comprising means for realizing an n0-th local Positive Operator Valued Measure on at least one initially selected subsystem Qn0 to thereby obtain a measurement outcome mn0, and a controller,
wherein said quantum computing device is operative, by control of the controller, to implement an initial measurement step which comprises for at least one initially selected subsystem Qn0 the realization of the n0-th local Positive Operator Valued Measure on said initially selected subsystem Qn0 to thereby obtain the measurement outcome mn0 and to implement an iterative measurement step which comprises for at least one iteratively selected subsystem Qn a realization of an n-th local Positive Operator Valued Measure on said iteratively selected subsystem Qn by implementing, by operation of said quantum computing device, said potentially imperfect realization of said joint unitary operation Un,nc followed by said joint quantum measurement described by said plurality of measurement operators
M
m
n
,
n
c
(
n
,
n
c
)
on said joint system of said iteratively selected subsystem Qn and said at least one connected subsystem Qnc, wherein said at least one connected subsystem Qnc is in a previously determined quantum state described by a density operator ρnc, to thereby obtain a measurement outcome mn,nc,
wherein for at least one iteratively selected subsystem Qn at least one of said connected subsystems Qnc, and each of said connected subsystems Qnc, is one of said at least one initially selected subsystems Qn0.

40 more elements

Dependencies are inferred from the claim text.