Qubit channels with small correlations

We introduce a class of quantum channels with correlations acting on pairs of qubits, where the correlation takes the form of a shift operator onto a maximally entangled state. We optimise the output purity and show that below a certain threshold the optimum is achieved by partially entangled states whose degree of entanglement increases monotonically with the correlation parameter. Above this threshold, the optimum is achieved by the maximally entangled state characterizing the shift. Although, a full analysis can only be done for the 2-norm, both numerical and heuristic arguments indicate that this behavior and the optimal inputs are independent of p>1 when the optimal output purity is measured using the p-norm.Comment: 11 pages, 4 figures, 2 table

Effect of curd suppression of a calf milk replacer fed at increasing levels on nutrient digestibility and body mass-gain

Two groups of eight Friesland bull calves each were used in the trial. Calves received a commercial, coagulable milk replacer in which casein coagulation either was normal (CM treatment), or was prevented by the precipitation of Ca++ with an oxalic acid-sodium hydroxide buffer (NCM treatment). In both treatments, the daily milk replacer feeding level (percentage of birth mass) was increased from 9% (week 1), to 12% (week 2), 15% (week 3) and 18% (week 4). Calves were weighed at weekly intervals and occurrence of diarrhoea was monitored. At four weeks of age, five calves from each treatment were randomly selected for a digestibility trial of seven days. Body mass-gain and efficiency of feed conversion (kg dry matter/kg gain) were 10,4 kg and 1,7; and 10,7 kg and 1,6 for the CM and NCM treatments, respectively. Digestibility coefficients were 90,2 and 91,1 % (dry matter), 91,9 and 93,6% (organic matter), and 81,0 and 85,6% (crude protein), for CM and NCM respectively. It was concluded that prevention of abomasal curd formation had no effect on body mass-gain, occurrence of diarrhoea, or digestibility of dry matter, organic matter and crude protein. Digestibility coefficients remained high, even at a daily feeding level of 18% of birth mass.Twee groepe van agt Friesbulkalwers elk is in die proef gebruik. Kalwers het 'n kommersiele, koaguleerbare melksurrogaat ontvang waarin koagulering of normaal was (CM-behandeling), of voorkom is deur die presipitering van Ca++ met 'n oksaalsuur-natriumhidroksiedbuffer (NCM-behandeling). Daaglikse melksurrogaatvoedingspeil (persentasie van geboortemassa) het in albei behandelings toegeneem vanaf 9% (week 1), tot 12% (week 2), 15% (week 3) en 18% (week 4). Kalwers is weekliks geweeg en die voorkoms van diarree is gemonitor. Vyf kalwers uit elke groep is op vier-weke-ouderdom ewekansig geselekteer vir 'n verteringsproef van sewe dae. Massatoename en doeltreffendheid van voeromsetting (kg droemateriaal/kg toename) was 10,4 kg en 1,7; en 10,7 kg en 1,6 vir die CM- en NCMbehandelings onderskeidelik. Verteerbaarheidskoeffisiente was 90,2 en 91,1% (droemateriaal), 91,9 en 93,6% (organiese materiaal) en 81,0 en 85,6% (ruprotei'en) vir CM en NCM, onderskeidelik. Die gevolgtrekking is gemaak dat voorkoming van abomasale stolselvorming geen invloed op massatoename, voorkoms van diarree, of die verteerbaarheid van droemateriaal, organiese materiaal en ruprotei'en gehad het nie. Verteerbaarheidskoeffisiente het hoog gebly, selfs teen 'n daaglikse voedingspeil van 18% van geboortemassa.Keywords: calves, milk replacers, casein, curd formation, digestibility, body mass-gai

Theory of impedance networks: The two-point impedance and LC resonances

We present a formulation of the determination of the impedance between any two nodes in an impedance network. An impedance network is described by its Laplacian matrix L which has generally complex matrix elements. We show that by solving the equation L u_a = lambda_a u_a^* with orthonormal vectors u_a, the effective impedance between nodes p and q of the network is Z = Sum_a [u_{a,p} - u_{a,q}]^2/lambda_a where the summation is over all lambda_a not identically equal to zero and u_{a,p} is the p-th component of u_a. For networks consisting of inductances (L) and capacitances (C), the formulation leads to the occurrence of resonances at frequencies associated with the vanishing of lambda_a. This curious result suggests the possibility of practical applications to resonant circuits. Our formulation is illustrated by explicit examples.Comment: 21 pages, 3 figures; v4: typesetting corrected; v5: Eq. (63) correcte

Spin-lattice coupling in the ferrimagnetic semiconductor FeCr2S4 probed by surface acoustic waves

Using surface acoustic waves, the elastomagnetic coupling could be studied in thin single crystalline plates of the ferrimagnetic semiconductor FeCr2S4 by measuring the attenuation and the frequency tracking in the temperature range 4.2 K to 200 K. The data clearly display the anomalies found in low-field magnetization measurements.Comment: 15 pages, 3 figures. To appear in J. Appl. Phys., 99 (2006

Generalized Induced Norms

Let ||.|| be a norm on the algebra M_n of all n-by-n matrices over the complex field C. An interesting problem in matrix theory is that "are there two norms ||.||_1 and ||.||_2 on C^n such that ||A||=max{||Ax||_2: ||x||_1=1} for all A in M_n. We will investigate this problem and its various aspects and will discuss under which conditions ||.||_1=||.||_2.Comment: 8 page

Classification of multipartite entanglement containing infinitely many kinds of states

We give a further investigation of the range criterion and Low-to-High Rank Generating Mode (LHRGM) introduced in \cite{Chen}, which can be used for the classification of $2\times{M}\times{N}$ states under reversible local filtering operations. By using of these techniques, we entirely classify the family of $2\times4\times4$ states, which actually contains infinitely many kinds of states. The classifications of true entanglement of $2\times(M+3)\times(2M+3)$ and $2\times(M+4)\times(2M+4)$ systems are briefly listed respectively.Comment: 11 pages, revte