We propose a hybrid quantum gate between an atom and a microwave photon in a superconducting coplanar waveguide cavity by exploiting the strong resonant microwave coupling between adjacent Rydberg states. Using experimentally achievable parameters gate fidelities >0.99 are possible on submicrosecond time scales for waveguide temperatures below 40 mK. This provides a mechanism for generating ent...

Quantum-dot Cellular Automata (QCA) technology is attractive due to its low power consumption, fast speed and small dimension, therefore, it is a promising alternative to CMOS technology. In QCA, configuration of charges plays the role which is played by current in CMOS. This replacement provides the significant advantages. Additionally, exclusive-or (XOR) gate is a useful building block in man...

23284 We describe a paradigm for measuring a single electron spin in the solid state. This technique can be used to " read " a spin qubit relatively non-invasively in either a spintronic quantum gate or a spintronic quantum memory. The spin reader can be self assembled by simple electrochemical techniques and can be integrated with a quantum gate.

We give quantum circuits that simulate an arbitrary two-qubit unitary operator up to global phase. For several quantum gate libraries we prove that gate counts are optimal in worst and average cases. Our lower and upper bounds compare favorably to previously published results. Temporary storage is not used because it tends to be expensive in physical implementations. For each gate library, best...

We investigate the influence of space-quantization effect and poly-gate depletion on the inversion layer capacitance Cinv, total gate capacitance Ctot and threshold voltage VT in scaled Si-MOSFETs. We also present an analytical expression for the total gate capacitance Ctot that uses classical charge description and takes into account the depletion of the poly-silicon gates. Our simulation resu...

Novel digital technologies always lead to high density and very low power consumption. One of these concepts is Quantum-dot Cellular Automata (QCA), which is one of the new emerging nanotechnology-based on Coulomb repulsion. This article presents three architectures of logical “XOR” gate, a novel structure of two inputs “XOR” gate, which is used as a module to implement four inputs “XOR” gate a...

Certain quantum gates, such as the controlled-NOT gate, are symmetric in terms of the operation of the control system upon the target system and vice versa. However, no operational criteria yet exist for establishing whether or not a given quantum gate is symmetrical in this sense. We consider a restricted, yet broad, class of two-party controlled gate operations for which the gate transforms a...

It is shown that a quantum controlled-NOT gate simultaneously performs the logical functions of three distinct conditional local operations. Each of these local operations can be verified by measuring a corresponding truth table of four local inputs and four local outputs. The quantum parallelism of the gate can then be observed directly in a set of three simple experimental tests, each of whic...

We report coherent optical control of a biexciton (two electron-hole pairs), confined in a single quantum dot, that shows coherent oscillations similar to the excited-state Rabi flopping in an isolated atom. The pulse control of the biexciton dynamics, combined with previously demonstrated control of the single-exciton Rabi rotation, serves as the physical basis for a two-bit conditional quantu...