An n-Bit Adder Realized via Coherent Optical Parallel Computing

Abstract

The quantum properties of nanosystems present a new opportunity to enhance the power of classical computers, both for the parallelism of the computation and the speed of the optical operations. In this paper we present the COPAC project aiming at development of a ground-breaking nonlinear coherent spectroscopy combining optical addressing and spatially macroscopically resolved optical readout. The discrete structure of transitions between quantum levels provides a basis for implementation of logic functions even at room temperature. Exploiting the superposition of quantum states gives rise to the possibility of parallel computation by encoding different input values into transition frequencies. As an example of parallel single instruction multiple data calculation by a device developed during the COPAC project, we present a n-bit adder, showing that due to the properties of the system, the delay of this fundamental circuit can be reduced.

Coupling in quantum dot molecular hetero-assemblies

“…In the last few years, a great scientific effort has been made to deeply understand the coupling mechanisms among colloidal quantum dots (QDs) interacting with each other when spaced at nanometric and sub-nanometric distances. [1][2][3][4][5][6][7][8][9] The elucidation of the interaction mechanisms among the QDs both in solution and in solid-state can open the opportunity to realize highly efficient charge transfer systems for optoelectronic devices and take a jump towards new fancy applications like quantum computing, [2,3,10] spintronic devices, [11] biosensors, [12,13] solar cells [14,15] and chiralinduced spin selectivity effect. [16] In these applications, the surface chemistry of the QDs, often controlled by the ligands, [17] plays a key role and an adequate understanding of the type of coupling involved that takes also in consideration the role of the organic capping layer is needed.…”