88 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
Robust state stansfer and rotation through a spin chain via dark passage
Quantum state transfer through a spin chain via adiabatic dark passage is proposed. This technique is robust against control field fluctuations and unwanted environmental coupling of intermediate spins. Our method can be applied to spin chains with more than three spins. We also propose single qubit rotation using this technique
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
Quantum cloning machines for equatorial qubits
Quantum cloning machines for equatorial qubits are studied. For the case of 1
to 2 phase-covariant quantum cloning machine, we present the networks
consisting of quantum gates to realize the quantum cloning transformations. The
copied equatorial qubits are shown to be separable by using Peres-Horodecki
criterion. The optimal 1 to M phase-covariant quantum cloning transformations
are given.Comment: Revtex, 9 page
Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation
We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10-11 to 5.0 × 10-21). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10-6). Our results provide new evidence for the role of DNA methylation in blood pressure regulation
Cluster state quantum computation and the repeat-until-success scheme
International Journal of Modern Physics B221-233-43IJPB
Entanglement of a 2-qubit system coupled to a bath of quantum spin glass
10.1016/j.physa.2014.02.017Physica A: Statistical Mechanics and its Applications40354-64PHYA
Hybrid quantum computation based on repeat-until-success scheme
10.1088/1751-8113/40/28/S21Journal of Physics A: Mathematical and Theoretical40288165-817
The general q-oscillator algebra and its coherent states
Czechoslovak Journal of Physics48111423-142
Quantum Information Science: An Update
10.1088/1742-6596/739/1/012001Journal of Physics: Conference Series73911200
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