A bifunctional superconducting cell as flux qubit and neuron

Abstract

Josephson digital or analog ancillary circuits are an essential part of a large number of modern quantum processors. The natural candidate for the basis of tuning, coupling, and neromorphic co-processing elements for processors based on flux qubits is the adiabatic (reversible) superconducting logic cell. Using the simplest implementation of such a cell as an example, we have investigated the conditions under which it can optionally operate as an auxiliary qubit while maintaining its “classical” neural functionality. The performance and temperature regime estimates obtained confirm the possibility of practical use of a single-contact inductively shunted interferometer in a quantum mode in adjustment circuits for q-processors.

Optimisation Challenge for a Superconducting Adiabatic Neural Network That Implements XOR and OR Boolean Functions

“…These basic elements are the superconducting interferometers connected by the inductive synapse-see Figure 2. The formation of the activation functions (flux-to-flux transformations) on individual S c -neurons has been previously studied in detail in both classical [47][48][49] and quantum modes [55,56]. Here we consider the interaction between different parts of the system.…”

“…As an example, in Appendix B, we present the derivation of the Hamiltonian of the system shown in Figure 2. This approach is quite simple and convenient in the case of scaling the circuit to a larger number of layers in a neural network, as well as for numerical modelling of nonlinear dynamics and further study of the quantum mode of operation of the circuit [55,56], including taking into account the influence of environments. Solution of the system in Equation ( 5) gives the transfer characteristics of the input and output neurons as a response to the input magnetic flux in (1).…”

“…Previously, we presented the concept of an adiabatic interferometer-based superconducting neuron [47][48][49], capable of operating in classical and quantum modes with ultra-low energy dissipation per operation (in the zJ range) [50][51][52][53][54][55][56][57]. The development of an adiabatic perceptron requires the realisation of a large number of connections between neurons via superconducting synapses [47].…”