Yale University

Nicholas Frattini

Michel Devoret

Shyam Shankar

Steven M Girvin

Katrina Sliwa

Anirudh Narla

Shruti Puri

Jayameenakshi Venkatraman

Shantanu Mundhada

Xu Xiao

Uri Vool

Volodymyr Sivak

Rodrigo G Cortiñas

Techniques are describing for designing and operating a quantum oscillator. In contrast with conventional approaches to operating a quantum oscillator, the present techniques relate to an oscillator design that has less bare nonlinearity than is conventionally thought to be necessary for efficient operation. Moreover, the oscillator may be driven at a frequency that is detuned away from the frequency at which a nonlinear oscillator is typically driven. In particular, the detuned drive frequency may be substantially different from the typical drive frequency, and furthermore may be a frequency that may be expected to produce a low coherence time without also engineering the reduced nonlinearity described above. As a result, the combination of an engineered reduced nonlinearity combined with a detuned drive may result in a well behaved oscillator with a strong effective nonlinearity that exhibits significantly longer coherence times than conventional quantum oscillators.

Driven kerr nonlinear oscillator and related systems and methods

Parametrically pumped four-wave mixing is a key building block for many developments in the field of superconducting quantum information processing. However, undesired frequency shifts such as Kerr, cross-Ken and Stark shifts inherent with four-wave mixing, lead to difficulties in tuning up the desired parametric processes and, for certain applications, severely limit the fidelities of the resulting operations. Some embodiments include a Josephson four-wave mixing device consisting of a SQUID transmon coupled to a half-flux biased SNAIL transmon, a.k.a. capacitively shunted flux qubit. When the two transmon have matching frequencies, an interference effect cancels the negative Kerr of the SQUID transmon with the positive Kerr of the SNAIL transmon while preserving parametric four-wave mixing capabilities.

Josephson nonlinear circuit

A superconducting device includes two nodes and a Josephson junction coupled between the two nodes, wherein the Josephson junction is characterized by a superconducting phase difference, &#x3c6;, wherein the superconducting device has a potential that varies as a function of the superconducting phase difference, &#x3c6;, and has a single potential well. The potential has a non-zero cubic term and quartic term is zero. The Josephson junction may be a single small Josephson junction. The superconducting device may include a superconducting ring connected between the two nodes. The superconducting ring may include a first ring portion with a plurality of large Josephson junctions connected in series. The superconducting ring may also include a second ring portion that includes the single small Josephson junction in parallel with the plurality of large Josephson junctions between the two nodes.

Superconducting nonlinear asymmetric inductive element and related systems and methods

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New Haven, CT, United States of America

Nicholas Frattini