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US 9,793,913 B2Granted
Single-flux-quantum probabilistic digitizer
AssigneeInternational Business Machines Corporation
InventorsJohn F. Bulzacchelli, Mark B. Ketchen, Christopher B. Lirakis, Alexey Y. Lvov, Stanislav Polonsky, Mark B. Ritter
Life of this patent
Estimating the term…
Abstract
A probabilistic digitizer for extracting information from a Josephson comparator is disclosed. The digitizer uses statistical methods to aggregate over a set of comparator readouts, effectively increasing the sensitivity of the comparator even when an input signal falls within the comparator's gray zone. Among other uses, such a digitizer may be used to discriminate between states of a qubit.
Claims18
A method comprising:
- receiving a plurality of sample sets, with each sample set including N sequential samples;
- for each given sample set of the plurality of sample sets:
- estimating a probability p(j) of an output pulse being produced from a Josephson comparator based on the N sequential samples of the given sample set, and
- estimating an analog input current Ix(j) corresponding to the given sample set based on an inverse function of p(j) for the given sample set using a probability curve Prob(Ix);
- and
- extracting a signal from output of the Josephson comparator based, at least in part upon the analog input current Ix(j) values respectively corresponding to the sample sets.
3 more elements
A computer program product comprising:
- a machine readable storage device;
- and
- computer code stored on the machine readable storage device, with the computer code including instructions for causing a processor(s) set to perform operations including the following:
- receiving a plurality of sample sets, with each sample set including N sequential samples,
- for each given sample set of the plurality of sample sets:
- estimating a probability p(j) of an output pulse being produced from a Josephson comparator based on the N sequential samples of the given sample set, and
- estimating an analog input current Ix(j) corresponding to the given sample set based on an inverse function of p(j) for the given sample set using a probability curve Prob(Ix);
- and
- extracting a signal from output of the Josephson comparator based, at least in part upon the analog input current Ix(j) values respectively corresponding to the sample sets.
6 more elements
A computer system comprising:
- a processor(s) set;
- a machine readable storage device;
- and
- computer code stored on the machine readable storage device, with the computer code including instructions for causing the processor(s) set to perform operations including the following:
- receiving a plurality of sample sets, with each sample set including N sequential samples,
- for each given sample set of the plurality of sample sets:
- estimating a probability p(j) of an output pulse being produced from a Josephson comparator based on the N sequential samples of the given sample set, and
- estimating an analog input current Ix(j) corresponding to the given sample set based on an inverse function of p(j) for the given sample set using a probability curve Prob(Ix);
- and
- extracting a signal from output of the Josephson comparator based, at least in part upon the analog input current Ix(j) values respectively corresponding to the sample sets.
7 more elements
Dependencies are inferred from the claim text.