The fractional Fourier transform (FRFT) is one-parametric generalization of the classical Fourier transform. FRFT was introduced in the 1980s and found a lot of applications in signal processing. The time and spectral...
详细信息
ISBN:
(纸本)9539676940
The fractional Fourier transform (FRFT) is one-parametric generalization of the classical Fourier transform. FRFT was introduced in the 1980s and found a lot of applications in signal processing. The time and spectral domains are both special cases of the fractional Fourier domain. They correspond to the Oth and 1st functional Fourier domains, respectively. We introduce the classical and quantum fractional Walsh transforms and develop corresponding fast algorithms.
We consider main properties of a neural field whose state is determined by a vector of some topological space (such as Banach or Hilbert ones). Dynamics of the field (time evolution of its state) is associated with in...
详细信息
We consider main properties of a neural field whose state is determined by a vector of some topological space (such as Banach or Hilbert ones). Dynamics of the field (time evolution of its state) is associated with informationprocessing and mental phenomena. We formulate the learning problem for neural fields and offer several solutions that are generalizations of learning algorithms proposed for neural networks before. The state vector of a neural field is represented in a form like in quantum theories, which gives a clue to a kind of supersymmetry, viz symmetry between bosonic and fermionic modes of excitation of the neural field. An evolution equation for a field function is suggested. A minimal architecture of a cognitive system is proposed which comprises perceptual, lexical and semantic subsystems. It is suggested to treat the meaning of a piece of information as a code associated with a settled field function produced by a semantic neural network.
quantuminformationprocessing offers potentially great advantages over classical informationprocessing, both for efficient algorithms(1,2) and for secure communication(3,4). Therefore, it is important to establish t...
quantuminformationprocessing offers potentially great advantages over classical informationprocessing, both for efficient algorithms(1,2) and for secure communication(3,4). Therefore, it is important to establish that scalable control of a large number of quantum bits (qubits) can be achieved in practice. There are a rapidly growing number of proposed device technologies(5-11) for quantuminformationprocessing. Of these technologies, those exploiting nuclear magnetic resonance (NMR) have been the first to demonstrate non-trivial quantumalgorithms with small numbers of qubits(12-16). To compare different physical realizations of quantuminformation processors, it is necessary to establish benchmark experiments that are independent of the underlying physical system, and that demonstrate reliable and coherent control of a reasonable number of qubits. Here we report an experimental realization of an algorithmic benchmark using an NMR technique that involves coherent manipulation of seven qubits. Moreover, our experimental procedure can be used as a reliable and efficient method for creating a standard pseudopure state, the first step for implementing traditional quantumalgorithms in liquid state NMR systems. The benchmark and the techniques can be adapted for use with other proposed quantum devices.
This paper surveys our recent research on quantuminformationprocessing by nuclear magnetic resonance (NMR) spectroscopy. We begin with a geometric introduction to the NMR of an ensemble of indistinguishable spins, a...
详细信息
This paper surveys our recent research on quantuminformationprocessing by nuclear magnetic resonance (NMR) spectroscopy. We begin with a geometric introduction to the NMR of an ensemble of indistinguishable spins, and then show how this geometric interpretation is contained within an algebra of multispin product operators. This algebra is used throughout the rest of the paper to demonstrate that it provides a facile framework within which to study quantuminformationprocessing more generally. The implementation of quantumalgorithms by NMR depends upon the availability of special kinds of mixed states, called pseudo-pure states, and we consider a number of different methods for preparing these states, along with analyses of how they scale with the number of spins. The quantum-mechanical nature of processes involving such macroscopic pseudo-pure states also is a matter of debate, and in order to discuss this issue in concrete terms we present the results of NMR experiments which constitute a macroscopic analogue Hardy's paradox. Finally, a detailed product operator description is given of recent NMR experiments which demonstrate a three-bit quantum error correcting code, using field gradients to implement a precisely-known decoherence model.
Magnetic recording channels perform several signal processing tasks in the process of storing and retrieving data. Among them are precompensation, equalization, timing recovery, detection, and coding. A range of algor...
Magnetic recording channels perform several signal processing tasks in the process of storing and retrieving data. Among them are precompensation, equalization, timing recovery, detection, and coding. A range of algorithms is available for each of these tasks with different levels of complexity and performance. We describe how each of these tasks is done today and indicate how they are likely to change as requirements and implementation technologies evolve. (C) 2000 American Institute of Physics. [S0021-8979(00)59908-3].
We give a short and simple proof of Hales and Hallgren's Fourier Sampling Theorem (Proceedings 31st Annual ACM Symp. Theory of Computing, ACM Press, 1999). The transparency of our proof-technique allows us to gene...
详细信息
We give a short and simple proof of Hales and Hallgren's Fourier Sampling Theorem (Proceedings 31st Annual ACM Symp. Theory of Computing, ACM Press, 1999). The transparency of our proof-technique allows us to generalize and tighten their result. (C) 2000 Elsevier Science B.V. All rights reserved.
Stabilizing quantumalgorithms against external perturbations and preserving quantum coherence are main challenges in the area of quantuminformationprocessing. In this contribution main ideas underlying a new class ...
详细信息
ISBN:
(纸本)0819441406
Stabilizing quantumalgorithms against external perturbations and preserving quantum coherence are main challenges in the area of quantuminformationprocessing. In this contribution main ideas underlying a new class of recently proposed embedded error-correcting quantum codes are discussed. These detected-jump correcting quantum codes are capable of stabilizing distinguishable qubits against spontaneous decay provided these decay processes originate from couplings to statistically independent reservoirs. Exploiting the classical information about which qubit has been affected by the environment these embedded quantum codes minimize the number of required control measurements and recovery operations as well as redundancy. Their stabilizing properties are exemplified by applying them to Grover's quantum search algorithm.
The effectiveness of utilizing spatial light modulators (SLMs), developed at Sanders, for reducing some of the critical bottlenecks inherent within the Hyperspectral Imaging (HSI) chain will be presented. Specifically...
详细信息
The effectiveness of utilizing spatial light modulators (SLMs), developed at Sanders, for reducing some of the critical bottlenecks inherent within the Hyperspectral Imaging (HSI) chain will be presented. Specifically, the more common classification, detection, and endmember selection algorithms used in HSI, which are suitable for optical implementation, are presented here. These algorithms were reformulated for implementation on a compact Vander-Lugt correlator based on Sanders' multi-level quantum well (MQW) spatial light modulator (SLM). Sanders devices are GaAs Fabry-Perot vertical cavity multiple quantum well (MQW) SLMs consisting of MQW optical chips flip-chip bonded to Si/CMOS driver circuitry. Details of the reformulation of Pixel Purity Index (PPI), an endmember selection algorithm, to the optical correlator is presented as well as a projection of its performance based on software simulations. In addition, hardware results are presented for Spectral Angle Mapper (SAM) based on a Vander-Lugt implementation using Sanders 128X128 binary SLMs. An opto-electronic hyperspectral workstation accelerator is proposed which is based on a Vander-Lugt correlator using Sanders MQW-SLMs and FPGA-based compute nodes and has the capability of 6.4 Million 1D correlations per second for HSI endmember selection, classification and detection.
Digital pulse processing is a signal processing technique in which detector (preamplifier output) signals are directly digitized and processed to extract quantities of interest. This approach has several significant a...
详细信息
Digital pulse processing is a signal processing technique in which detector (preamplifier output) signals are directly digitized and processed to extract quantities of interest. This approach has several significant advantages compared to traditional analog signal shaping. First, analyses can be developed which take pulse-by-pulse differences into account, as in making ballistic deficit compensations. Second, transient induced charge signals, which deposit no net charge on an electrode, can be analyzed to give, for example, information on the position of interaction within the detector. Third, deadtimes from transient overload signals are greatly reduced, from tens of mu s to hundreds of ns. Fourth, signals are easily captured, so that more complex analyses can be postponed until the source event has been deemed "interesting". Fifth, signal capture and processing may easily be based on coincidence criteria between different detectors or different parts of the same detector, XIAs recently introduced CAMAC module, the DGF-4C, provides many of these features for four input channels, including two levels of digital processing and a FIFO for signal capture for each signal channel. The first level of digital processing is "immediate", taking place in a gate array at the 40 MHz digitization rate, and implements pulse detection, pileup inspection, trapezoidal energy filtering, and control of an external 25.6 mu s long FIFO. The second level of digital processing is provided by a digital signal processor (DSP), where more complex algorithms can be implemented. To illustrate digital pulse processing's possibilities, we describe the application of the DGF-4C to a series of experiments. The first, for which the DGF was originally developed, involves locating gamma-ray interaction sites within large segmented Ge detectors. The goal of this work is to attain spatial resolutions of order 2 mm sigma within 70 mm x 90 mm detectors. We show how pulse shape analysis allows ballistic d
暂无评论