Josephson static random access memory
AssigneeImec Vzw
InventorsHenry Luo, Anna Yurievna Herr, Quentin Paul Herr
Life of this patent
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Abstract
Josephson junction based memory devices and methods for their use are described herein. An example Josephson junction based memory device includes a plurality of superconducting loops. Each superconducting loop includes at least one Josephson junction. The plurality of superconducting loops are electrically coupled. The plurality of superconducting loops include a plurality of input loops, a plurality of readout loops, and at least one shared loop. The plurality of superconducting loops are configured to store or annihilate magnetic flux quanta in one or more of the superconducting loops in response to a combination of control signals and single flux quantum (SFQ) pulses.
Claims16
A Josephson junction based memory device comprising:
- a plurality of superconducting loops wherein each superconducting loop comprises at least one Josephson junction, wherein the plurality of superconducting loops are electrically coupled in a series arrangement, wherein each superconducting loop of the plurality of superconducting loops has one or two adjacent loops, and wherein the plurality of superconducting loops comprises:
- a plurality of input loops;
- a plurality of readout loops;
- and
- at least one shared loop, wherein the plurality of superconducting loops are configured to store or annihilate magnetic flux quanta in one or more of the superconducting loops in response to a combination of control signals and single flux quantum (SFQ) pulses, wherein the plurality of superconducting loops are configured to shift a magnetic flux quanta from an initial superconducting loop to an adjacent loop in response to a SFQ pulse applied to the initial superconducting loop, wherein the magnetic flux quanta is shifted from an initial superconducting loop to an adjacent loop in a first direction along the series arrangement in response to a positive SFQ pulse polarity, and wherein the magnetic flux quanta is shifted from an initial superconducting loop to an adjacent loop in a second direction along the series arrangement in response to a negative SFQ pulse polarity.
A method for storing digital information in a Josephson junction based memory device comprising:
- providing, to a plurality of superconducting loops, a combination of control signals and single flux quantum (SFQ) pulses, wherein each superconducting loop comprises at least one Josephson junction, wherein the plurality of superconducting loops are electrically coupled, wherein the plurality of superconducting loops comprises:
- a plurality of input loops;
- a plurality of readout loops;
- and
- at least one shared loop;
- in response to the combination of control signals and SFQ pulses, storing or annihilating magnetic flux quanta in one or more of the superconducting loops;
- while cooling down the Josephson junction based memory device, providing an initialization signal via an at least one magnetically coupled control line;
- and
- upon reaching a superconducting critical temperature of the Josephson junction based memory device, turning off the initialization signal such that an exact integral number of SFQ are stored in the plurality of superconducting loops.
Dependencies are inferred from the claim text.