US 9,812,836 B1
Reversible computation with flux solitons
Kevin D. Osborn, Laurel, MD (US)
Assigned to The United States of America as represented by the Director, National Security Agency, Washington, DC (US)
Filed by The United States of America as represented by the Director, National Security Agency, Washington, DC (US)
Filed on Nov. 12, 2014, as Appl. No. 14/121,007.
Int. Cl. H01S 3/00 (2006.01); H01S 3/02 (2006.01)
CPC H01S 3/02 (2013.01) 20 Claims
OG exemplary drawing
 
1. A reversible superconducting circuit comprising:
a plurality of Josephson transmission lines, wherein:
each Josephson transmission line includes:
a discretized Long Josephson Junction, including:
a parallel array of Josephson Junctions; and
a plurality of superconducting inductors, wherein
the inductors connect the Josephson Junctions in the array;
each Josephson transmission line is configured to pass a fluxon along the length of the array of Josephson Junctions, the fluxon being a soliton having total flux equal to Φ0, where Φ0 is the magnetic flux quantum;
a first of the Josephson transmission lines is configured to transmit a first target fluxon from the first of the Josephson transmission lines to one of a first output and a second output only when a first target input is active;
a second of the Josephson transmission lines is configured to transmit a second target fluxon from the second of the Josephson transmission lines to one of the first output and the second output only when a second target input is active;
a third of the Josephson transmission lines is configured to transmit a control fluxon only when a control input is active, wherein:
the reversible superconducting circuit is configured to, when at least two fluxons are transmitted, transmit the fluxons substantially synchronously; and
a path of the first target fluxon and a path of the second target fluxon are determined at least in part by a presence or an absence of the control fluxon;
the superconducting circuit is configured to, if the control input is active:
transmit the first target fluxon to the first output only if the first target input is active; and
transmit the second target fluxon to the second output only if the second target input is active; and
the superconducting circuit is configured to, if the control input is not active:
transmit the first target fluxon to the second output only if the first target input is active; and
transmit the second target fluxon to the first output only if the second target input is active.