Relaxation method in description of RAM memory cell in RSFQ computer

Abstract

Purpose The lack of reliable and scalable superconducting random access memory (RAM) cells is the main obstacle for full implementation of superconducting rapid single flux quantum(RSFQ) computers. This work points the methodology and the structures that shall be used in future implementation of RSFQ RAM. Design/methodology/approach A new design for RAM using two ferromagnetic strips in proximity to the superconductor in a RSFQ computer is presented (1). The concept of using a RAM RSFQ cell as a tuneable superconducting qubit is also explored. Findings Two basic architectures for superconducting RAM cells were developed with integration schemes in two dimensions. Research limitations/implications The proposed RAM cells as depicted in Figures 7 and 16 offer smaller size and greater 3 scalability in comparison to other suggested schemes (4), (3), (2), (5). Practical implications Currently, the main obstacle in implementation of RSQF computer is lack of reliable RAM cell. RSQF computer shall have potential to take a large fraction of classical supercomputers, as it consumes much less power. Social implications Computation power shall be cheaper when one uses RSQF computers for big data and computational centres. It is a matter of some time. Originality/value The publication presents the new design of superconducting RAM cell for use in RSQF computer. The numerical relaxation method is used to solve biharmonic Ginzburg–Landau equation. The analytic approach as a solution of a specified problem is given.

Analytic view on N body interaction in electrostatic quantum gates and decoherence effects in tight-binding model

“…The usage of magnetic field is main obstacle in scalability of such structures so very high integration quantum circuits are not expected to take place. What is even more important the usage of low temperature superconductors that has superconducting coherence lenght of range of 300nm (it thus proportional to the size of Cooper pair) brings the limitation in further miniaturization of those structures [10], [15]. Suprisingly semiconductor technologies have no such limitations and most advanced CMOS transistors has the channgel lenght between source and drain of 3nm.…”

“…It opens the path for implementation of CMOS quantum computer that is only controlled by voltages applied to CMOS transistors with no need of usage of magnetic field. It is nice alternative for implementation of quantum electronics other than by the usage of Josephson junctions [7,12]. The best way of detection of entanglement present between electrostatically interacting qubits is by measure of the correlation-anticorrelation function that is achievable in experimental way.…”

Analytic view on coupled single-electron lines

“…x [1] [2] [3] (A): w L (x) and |0, 1 = w R (x) which underlines the presence of electron on the left/right side as equivalent to picture from Schrödinger equation [8].). We obtain two energy eigenstates…”

“…Moreover, it is commonly accepted by the technologists that the use of fractional electron charge has no practical meaning. On the other hand, the use of different representation of information as by fluxons (quantized flux of magnetic field) in Rapid Single Quantum Flux electronics turns out to have its limitations from the point of view of its size, as implementation in very large scale integration circuits [3]. In this work, we limit ourselves to the electrostatic description of an electron-electron interaction.…”