Programmable architecture for quantum computing

Abstract

A programmable architecture called "quantum FPGA (field-programmable gate array)" (QFPGA) is presented for quantum computing, which is a hybrid model combining the advantages of the qubus system and the measurement-based quantum computation. There are two kinds of buses in QFPGA, the local bus and the global bus, which generate the cluster states and general multiqubit rotations around the z axis, respectively. QFPGA consists of quantum logic blocks (QLBs) and quantum routing channels (QRCs). The QLB is used to generate a small quantum logic while the QRC is used to combine them properly for larger logic realization. Considering the error accumulating on the qubus, the small logic is the general two-qubit quantum gate. However, for the application such as n-qubit quantum Fourier transform, one QLB can be reconfigured for four-qubit quantum Fourier transform. Although this is an implementation-independent architecture, we still make a rough analysis of its performance based on the qubus system. In a word, QFPGA provides a general architecture to integrate different quantum computing models for efficient quantum logic construction.

The physics of thermal light second-order interference beyond coherence

“…at the detection time t d around the mean value I d (t d ) , at each detector d = C, T , can be measured by using single-photon detectors with integration time δt 1/∆ω [53,54]. One can than evaluate the correlation in the intensity fluctuations at the two output ports [53,54,5]…”

Parallel Quantum Circuit in a Tunnel Junction

“…This system was obtained after calculating the C a (t),C b (t),C 1 (t), ...C N (t) coordinates of |Ψ(t) on the canonical basis set, after taking into account the symmetry of the A − N − B system i.e. C 1 (t) = C 2 (t) = ... = C N (t) = C(t) and finally after performing the transformatioñ C(t) = √ NC(t) as implemented in [2]. After solving (3) analytically, the variation in time of the |φ b population amplitude is given by:…”

“…In this case, the N 2 law is no more valid with a saturation of T (E f , N) 1 whatever the large N values and a decreasing of T (E f , N) 2 for large N after its saturation to unity. T (E f , N) 2 In Figure (5), the range of the N 2 law validity is presented by plotting the…”

“…Installing a quantum transfer line in between two identical A and B quantum systems opens the possibility to transfer from A to B one electron added to A because of the electronic coupling introduced between A and B by this line [1,2]. To increase the chance for this electron to be transferred, to speed up its transfer or to minimize the energy required, more transfer lines can be added in parallel forming a quantum bus between A and B [2]. In absence of electronic coupling between the lines, N identical lines in parallel must intuitively increase the V ab (N) coupling between state |φ a (electron on A) and state |φ b (the electron on B).…”

“…In absence of electronic coupling between the lines, N identical lines in parallel must intuitively increase the V ab (N) coupling between state |φ a (electron on A) and state |φ b (the electron on B). Quantifying the V ab (N) power law of this superposition and measuring it experimentally are long standing problems [1,2]. A possible measure (i) is to perform a spectroscopy characterization of the A − N − B quantum system to follow how the free from bus |φ a , |φ b degeneracy is lifted up by the progressive insertion of N lines in parallel between A and B.…”