1,280 research outputs found
Quantum tunneling time
A simple model of a quantum clock is applied to the old and controversial
problem of how long a particle takes to tunnel through a quantum barrier. The
model I employ has the advantage of yielding sensible results for energy
eigenstates, and does not require the use of time-dependant wave packets.
Although the treatment does not forbid superluminal tunneling velocities, there
is no implication of faster-than-light signaling because only the transit
duration is measurable, not the absolute time of transit. A comparison is given
with the weak-measurement post-selection calculations of Steinberg.Comment: 10 pages, no figures, research pape
Mitigating smart card fault injection with link-time code rewriting: a feasibility study
We present a feasibility study to protect smart card software against fault-injection attacks by means of binary code rewriting. We implemented a range of protection techniques in a link-time rewriter and evaluate and discuss the obtained coverage, the associated overhead and engineering effort, as well as its practical usability
Better detection of Multipartite Bound Entanglement with Three-Setting Bell Inequalities
It was shown in Phys. Rev. Lett., 87, 230402 (2001) that N (N >= 4) qubits
described by a certain one parameter family F of bound entangled states violate
Mermin-Klyshko inequality for N >= 8. In this paper we prove that the states
from the family F violate Bell inequalities derived in Phys. Rev. A, 56, R1682
(1997), in which each observer measures three non-commuting sets of orthogonal
projectors, for N >=7. We also derive a simple one parameter family of
entanglement witnesses that detect entanglement for all the states belonging to
F. It is possible that these new entanglement witnesses could be generated by
some Bell inequalities.Comment: Revtex4, 1 figur
Entanglement and Berry Phase in a dimensional Yang-Baxter system
Based on the method which is given in Ref. [Sun et.al. arXiv:0904.0092v1], we
present another unitary matrix, solution of the
Yang-Baxter Equation, is obtained in this paper. The entanglement properties of
matrix is investigated, and the arbitrary degree of entanglement
for two-qutrit entangled states can be generated via -matrix acting
on the standard basis. A Yang-Baxter Hamiltonian can be constructed from
unitary matrix. Then the geometric properties of this system is
studied. The results showed that the Berry phase of this system can be
represented under the framework of SU(2) algebra.Comment: 6 page
Fidelity of Quantum Teleportation through Noisy Channels
We investigate quantum teleportation through noisy quantum channels by
solving analytically and numerically a master equation in the Lindblad form. We
calculate the fidelity as a function of decoherence rates and angles of a state
to be teleported. It is found that the average fidelity and the range of states
to be accurately teleported depend on types of noise acting on quantum
channels. If the quantum channels is subject to isotropic noise, the average
fidelity decays to 1/2, which is smaller than the best possible value 2/3
obtained only by the classical communication. On the other hand, if the noisy
quantum channel is modeled by a single Lindblad operator, the average fidelity
is always greater than 2/3.Comment: 6 pages, 5 figures, accepted for publication in Phys. Rev.
On Bures fidelity of displaced squeezed thermal states
Fidelity plays a key role in quantum information and communication theory.
Fidelity can be interpreted as the probability that a decoded message possesses
the same information content as the message prior to coding and transmission.
In this paper, we give a formula of Bures fidelity for displaced squeezed
thermal states directly by the displacement and squeezing parameters and
birefly discuss how the results can apply to quantum information theory.Comment: 10 pages with RevTex require
Dynamical fluctuations in classical adiabatic processes: General description and their implications
Dynamical fluctuations in classical adiabatic processes are not considered by
the conventional classical adiabatic theorem. In this work a general result is
derived to describe the intrinsic dynamical fluctuations in classical adiabatic
processes. Interesting implications of our general result are discussed via two
subtopics, namely, an intriguing adiabatic geometric phase in a dynamical model
with an adiabatically moving fixed-point solution, and the possible "pollution"
to Hannay's angle or to other adiabatic phase objects for adiabatic processes
involving non-fixed-point solutions.Comment: 19 pages, no figures, discussion significantly expanded, published
versio
A note on the geometric phase in adiabatic approximation
The adiabatic theorem shows that the instantaneous eigenstate is a good
approximation of the exact solution for a quantum system in adiabatic
evolution. One may therefore expect that the geometric phase calculated by
using the eigenstate should be also a good approximation of exact geometric
phase. However, we find that the former phase may differ appreciably from the
latter if the evolution time is large enough.Comment: 11 pages, no figure, modified and Journal-ref adde
Effects of various additives to enhance growth performance, blood profiles, and reduce malodour emissions in growing pigs
Experiment 1 was a feeding trial in which 75 (Landrace ⅹ Yorkshire) ⅹ Duroc pigs with average initial bodyweight (BW) of 26 ± 1 kg were used. It was assigned to three pigs/pen and five pens/treatment. Experiment 2 was a metabolic trial in which 25 (LandraceⅹYorkshire)ⅹDuroc pigs with average initial bodyweight (BW) of 36 ± 1 kg were used. The basal diet consisted of maize (57.71 %), soybean meal (32.45 %), and wheat bran (5 %). Treatments consisted of i) CON (control diet); ii) OE (organic acid + essential oils) (Aviplus-S®), that is, CON + 0.05 % OE; iii) OC (organic charcoal) (Olga Black®), that is, CON + 0.1 % OC; iv) AE (anise extracts) (RESQ®), that is, CON + 0.015 % AE; and v) PB (probiotics) (Bonvital®), that is, CON + 0.1 % PB. Average daily gain (ADG) and gain/feed ratio (G : F) were significantly higher in the OE and AE groups than in the others. Average daily feed intake (ADFI) for OE, OC, and AE treatments was significantly higher than that for CON and PB treatments. Dry matter (DM) digestibility was significantly higher in AE than CON. Crude protein (CP) was significantly higher in OE, AE, and PB than CON. CON and other treatments did not cause significant differences in blood l-density lipoprotein (LDL), and glucose. NH3 emissions were significantly lower in all treated groups than in CON. Among the treatments, NH3 emissions were lowest in OE and AE. H2S emissions were significantly lower in OE, AE, and PB than in CON. Among the treatments, OE and AE were most effective at reducing H2S emissions. The emissions of volatile fatty acids (VFAs) showed no significant difference between treatments and CON. In conclusion, this experiment was shown to be more effective on growth performance, malodour emission, blood profiles, and nutrient digestibility in OE and AE than other additives.Keywords: Digestibility, feed, influence, odour, supplementation, swin
Effects of reducing dietary crude protein and metabolic energy in weaned piglets
The objective of this experiment was to determine the effects of a pure reduction in the dietary crude protein (CP) and metabolic energy (ME) contents on growth performance, nutrient digestibility, blood profile, faecal microflora and odour gas emission in weaned pigs. A total of 80 weaned piglets ((Landrace × Yorkshire) × Duroc) with a mean initial bodyweight (BW) of 6.8 ± 0.5 kg were randomly allotted to four treatments with four replicate pens of five piglets per pen (based on average BW) for 45 days. The dietary treatments consisted of i) CON: basal diet; ii) LME: reduction of 10% of ME in basal diet; iii) LCP: reduction of 10% of CP in basal diet; iv) MECP: reduction of 10% of CP and 10% of ME in basal diet. During the experimental period, average daily feed intake (ADFI) improved in piglets fed the LME and LCP diets, compared with those fed the CON diets. Average daily gain (ADG) and gain to feed (G : F) ratio decreased in piglets fed LCP, LME, and MECP diet, when compared with those fed the CON diet. However, during the total experimental period, ADG and G : F ratio were not affected by dietary treatment. With regard to nutrient digestibility, apparent total track digestibility (ATTD) of CP was not affected by experimental diets. The concentration of blood urea nitrogen (BUN) in blood decreased more in piglets fed LME, LCP, and MECP than those fed the CON diet. The emissions of ammonia (NH3), hydrogen sufide (H2S), and volatile fatty acids (VFAs) were lower in piglets fed LME, LCP, and MECP diet than those fed the CON diet. In conclusion, these results indicate that reduction in dietary CP and ME content did not decrease growth performance and nutrient digestibility, and they increased positive effects such as BUN and gas emission reduction.Keywords: Blood profile, digestibility, growth performance, odour emission, pi
- …