19 research outputs found
Single-Electron Parametron: Reversible Computation in a Discrete State System
We have analyzed energy dissipation in a digital device (``Single-Electron
Parametron'') in which discrete degrees of freedom are used for presenting
digital information. If the switching speed is not too high, the device may
operate reversibly (adiabatically), and the energy dissipation per
bit may be much less than the thermal energy . The energy-time product
is, however, much larger than Planck's constant , at
least in the standard ``orthodox'' model of single-electron tunneling, which
was used in our calculations.Comment: 9 pages, RevTex, 3 figure
A Possible Nanometer-scale Computing Device Based on an Adding Cellular Automaton
We present a simple one-dimensional Cellular Automaton (CA) which has the
property that an initial state composed of two binary numbers evolves quickly
into a final state which is their sum. We call this CA the Adding Cellular
Automaton (ACA). The ACA requires only 2N two-state cells in order to add any
two N-1 bit binary numbers. The ACA could be directly realized as a wireless
nanometer-scale computing device - a possible implementation using coupled
quantum dots is outlined.Comment: 8 pages, RevTex, 3 Postscript figures. This version to appear in App.
Phys. Let
Coulomb Blockade and Digital Single-Electron Devices
Tunneling of single electrons has been thoroughly studied both theoretically
and experimentally during last ten years. By the present time the basic physics
is well understood, and creation of useful single-electron devices becomes the
important issue. Single-electron tunneling seems to be the most promising
candidate to be used in the future integrated digital circuits with the typical
size scale of few nanometers and below, i.e. in the molecular electronics. In
the review we first briefly discuss the physics of single-electron tunneling
and the operation of the single-electron transistor. After that, we concentrate
on the hypothetical ultradense digital single-electron circuits and discuss the
different proposed families of them. The last part of the review considers the
issues of the discrete energy spectrum and the finite tunnel barrier height
which are important for the molecular-size single-electron devices.Comment: Review paper, to be published in "Molecular Electronics", ed. by J.
Jortner and M. A. Ratner (Blackwell, Oxford). 49 pages, RevTex, 15 figure
Computing with spins: From classical to quantum computing
This article traces a brief history of the use of single electron spins to
compute. In classical computing schemes, a binary bit is represented by the
spin polarization of a single electron confined in a quantum dot. If a weak
magnetic field is present, the spin orientation becomes a binary variable which
can encode logic 0 and logic 1. Coherent superposition of these two
polarizations represent a qubit. By engineering the exchange interaction
between closely spaced spins in neighboring quantum dots, it is possible to
implement either classical or quantum logic gates.Comment: 3 figure
Adiabatic quantum computation with Cooper pairs
We propose a new variant of the controlled-NOT quantum logic gate based on
adiabatic level-crossing dynamics of the q-bits. The gate has a natural
implementation in terms of the Cooper pair transport in arrays of small
Josephson tunnel junctions. An important advantage of the adiabatic approach is
that the gate dynamics is insensitive to the unavoidable spread of junction
parameters.Comment: 18 pages, 3 figures not supplied by autho
Beyond Moore's technologies: operation principles of a superconductor alternative
The predictions of Moore's law are considered by experts to be valid until
2020 giving rise to "post-Moore's" technologies afterwards. Energy efficiency
is one of the major challenges in high-performance computing that should be
answered. Superconductor digital technology is a promising post-Moore's
alternative for the development of supercomputers. In this paper, we consider
operation principles of an energy-efficient superconductor logic and memory
circuits with a short retrospective review of their evolution. We analyze their
shortcomings in respect to computer circuits design. Possible ways of further
research are outlined.Comment: OPEN ACCES