Realization of a Functional Cell for Quantum-Dot Cellular Automata

Abstract

Tukey methods [G. M. Jenkins and D. G. Watts, Spectral Analysis and its Applications (Holden-Day, Oakland, CA, 1968)] to the ␦ 18 O anomalies resolves statistically significant (minimum of 80% level) spectral peaks at 12.2-, 8.3-, 5.5-, 3.78-, 2.3-, and 1.7-year periods. The maximum entropy method places these peaks at 11.4, 7.8, 5.5, and 3.5, 2.3, and 1.7 years. 13. We used singular spectrum analysis (SSA) [R. Vautard and M. Ghil, Physica D 35, 395 (1989)] to reconstruct the most energetic modes in the coral record. After the removal of the seasonal cycle and the longterm trend, with a window length of M ϭ 39 years, SSA produces two modes in clean quadrature: modes 1 and 2, with a period of 11.8 years, and modes 3 and 4, with a period of 5.3 years (modes with periods greater than 39 years are unresolved). After the further removal of the decadal and interdecadal modes and with a window length of M ϭ 25 years, two modes emerge in quadrature: modes 1 and 2, with a period of 5.3 years, and modes 3 and 4, with a period of 3.5 years. The quasi-biennial signal emerges in clean quadrature when a 10-year window length is used. Monte Carlo simulations suggest that all of these modes represent statistically significant (at the 95% confidence level) concentrations of variance. More conventional band-pass filtering yields nearly identical patterns.

Stacked Ge islands for photovoltaic applications

“…Since the islands can be formed without introducing misfit dislocations and complicated lithography techniques, the SK growth mode is regarded as a promising route towards the fabrication of nanoscale islands, which might act as quantum dots (QDs). The most possible electronic applications of QDs include quantum cellular automata [6] and single electron transistors require precise control of the size and the position of QDs. Notwithstanding several approaches such as growth on patterned substrates [7 -15] have been carried out to accomplish the requirement, it still remains a critical issue.…”

Self-assembled periodicFe3O4nanostructures in ultrathin FeO(111) films on Ru(0001)

“…Currently, the development of ordered metal and semiconductor nanostructures at an atomic scale with future applications as semiconducting nanodevices or quantum dotbased lasers have gained significant interest [1,2]. Arbitrary atomic scale structures are accessible by displacing atoms with the tip of a scanning tunneling microscope (STM) [3].…”

Energy barrier to decoherence

“…2, we suggest how the controlled-NOT gate could be realized physically in a quantum-dot implementation. The connection (11)(12)(13)(14) proceeds through twobody interactions, in which the electric field of the electron in the control qubit influences the tunneling matrix elements and on-site energies in the target qubit and vice versa.…”

“…Our scheme works exclusively with quantum mechanical ground states, completely obviating the need for time-dependent control of a system. While researchers have considered using quantum mechanical ground states to perform classical computations [10][11][12], the idea of executing quantum algorithms using a ground state computer is an exciting unexplored possibility.In traditional quantum computation, one examines the development in time of a collection of quantum mechanical "qubits" under controlled unitary evolutions [13]. Each qubit is a two-state system, described by inner products of the quantum mechanical state |ψ(t) with basis states |0 and |1 associated with the 0 and 1 bit values.…”

“…Our scheme works exclusively with quantum mechanical ground states, completely obviating the need for time-dependent control of a system. While researchers have considered using quantum mechanical ground states to perform classical computations [10][11][12], the idea of executing quantum algorithms using a ground state computer is an exciting unexplored possibility.…”