37,949 research outputs found
Period halving of Persistent Currents in Mesoscopic Mobius ladders
We investigate the period halving of persistent currents(PCs) of
non-interacting electrons in isolated mesoscopic M\"{o}bius ladders without
disorder, pierced by Aharonov-Bhom flux. The mechanisms of the period halving
effect depend on the parity of the number of electrons as well as on the
interchain hopping. Although the data of PCs in mesoscopic systems are
sample-specific, some simple rules are found in the canonical ensemble average,
such as all the odd harmonics of the PCs disappear, and the signals of even
harmonics are non-negative. {PACS number(s): 73.23.Ra, 73.23.-b, 68.65.-k}Comment: 6 Pages with 3 EPS figure
Fast decoding of a d(min) = 6 RS code
A method for high speed decoding a d sub min = 6 Reed-Solomon (RS) code is presented. Properties of the two byte error correcting and three byte error detecting RS code are discussed. Decoding using a quadratic equation is shown. Theorems and concomitant proofs are included to substantiate this decoding method
On the undetected error probability of a concatenated coding scheme for error control
Consider a concatenated coding scheme for error control on a binary symmetric channel, called the inner channel. The bit error rate (BER) of the channel is correspondingly called the inner BER, and is denoted by Epsilon (sub i). Two linear block codes, C(sub f) and C(sub b), are used. The inner code C(sub f), called the frame code, is an (n,k) systematic binary block code with minimum distance, d(sub f). The frame code is designed to correct + or fewer errors and simultaneously detect gamma (gamma +) or fewer errors, where + + gamma + 1 = to or d(sub f). The outer code C(sub b) is either an (n(sub b), K(sub b)) binary block with a n(sub b) = mk, or an (n(sub b), k(Sub b) maximum distance separable (MDS) code with symbols from GF(q), where q = 2(b) and the code length n(sub b) satisfies n(sub)(b) = mk. The integerim is the number of frames. The outercode is designed for error detection only
An extended d(min) = 4 RS code
A minimum distance d sub m - 4 extended Reed - Solomon (RS) code over GF (2 to the b power) was constructed. This code is used to correct any single byte error and simultaneously detect any double byte error. Features of the code; including fast encoding and decoding, are presented
Heralded Entanglement between Atomic Ensembles: Preparation, Decoherence, and Scaling
Heralded entanglement between collective excitations in two atomic ensembles
is probabilistically generated, stored, and converted to single photon fields.
By way of the concurrence, quantitative characterizations are reported for the
scaling behavior of entanglement with excitation probability and for the
temporal dynamics of various correlations resulting in the decay of
entanglement. A lower bound of the concurrence for the collective atomic state
of 0.9\pm 0.3 is inferred. The decay of entanglement as a function of storage
time is also observed, and related to the local dynamics.Comment: 4 page
Pairing Correlations Near a Kondo-Destruction Quantum Critical Point
Motivated by the unconventional superconductivity observed in heavy-fermion
metals, we investigate pairing susceptibilities near a continuous quantum phase
transition of the Kondo-destruction type. We solve two-impurity Bose-Fermi
Anderson models with Ising and Heisenberg forms of the interimpurity exchange
interaction using continuous-time quantum Monte-Carlo and numerical
renormalization-group methods. Each model exhibits a Kondo-destruction quantum
critical point separating Kondo-screened and local-moment phases. For
antiferromagnetic interimpurity exchange interactions, singlet pairing is found
to be enhanced in the vicinity of the transition. Implications of this result
for heavy-fermion superconductivity are discussed.Comment: 5 pages, 5 figures + supplementary material 2 page, 2 figures:
Replaced with published versio
Error control for reliable digital data transmission and storage systems
A problem in designing semiconductor memories is to provide some measure of error control without requiring excessive coding overhead or decoding time. In LSI and VLSI technology, memories are often organized on a multiple bit (or byte) per chip basis. For example, some 256K-bit DRAM's are organized in 32Kx8 bit-bytes. Byte oriented codes such as Reed Solomon (RS) codes can provide efficient low overhead error control for such memories. However, the standard iterative algorithm for decoding RS codes is too slow for these applications. In this paper we present some special decoding techniques for extended single-and-double-error-correcting RS codes which are capable of high speed operation. These techniques are designed to find the error locations and the error values directly from the syndrome without having to use the iterative alorithm to find the error locator polynomial. Two codes are considered: (1) a d sub min = 4 single-byte-error-correcting (SBEC), double-byte-error-detecting (DBED) RS code; and (2) a d sub min = 6 double-byte-error-correcting (DBEC), triple-byte-error-detecting (TBED) RS code
Fast decoding techniques for extended single-and-double-error-correcting Reed Solomon codes
A problem in designing semiconductor memories is to provide some measure of error control without requiring excessive coding overhead or decoding time. For example, some 256K-bit dynamic random access memories are organized as 32K x 8 bit-bytes. Byte-oriented codes such as Reed Solomon (RS) codes provide efficient low overhead error control for such memories. However, the standard iterative algorithm for decoding RS codes is too slow for these applications. Some special high speed decoding techniques for extended single and double error correcting RS codes. These techniques are designed to find the error locations and the error values directly from the syndrome without having to form the error locator polynomial and solve for its roots
- …