2,756 research outputs found
Information loss in local dissipation environments
The sensitivity of entanglement to the thermal and squeezed reservoirs'
parameters is investigated regarding entanglement decay and what is called
sudden-death of entanglement, ESD, for a system of two qubit pairs. The
dynamics of information is investigated by means of the information disturbance
and exchange information. We show that for squeezed reservoir, we can keep both
of the entanglement and information survival for a long time. The sudden death
of information is seen in the case of thermal reservoir
Structural diversity of frameshifting signals : reprogramming the programmed
Programmed ribosomal frameshifting (PRF) is one kind of recoding events that is mostly utilized by RNA viruses to synthesize more proteins with defined ratio from their compact genome and it is known that the stoichiometric is critical to virus infection and propagation. Two cis-acting RNA elements are critical to induce PRF: one is slippery sequence where the frameshifting occurs and the other is RNA secondary structure, either a stem-loop or pseudoknot, to stall ribosomes on the slip site. In this thesis, we first demonstrate that a stem-loop structure can efficient replace pseudoknot in inducing frameshifting, arguing previous assumption hairpins are efficient frameshiftors. Furthermore, we show antisense oligonucleotides (AON) that mimic hairpin or pseudoknot can promote efficient frameshifting suggesting the downstream secondary structures act as physical barriers in frameshifting. Finally, we report a novel ligand responsive frameshifting signal derived from non-frameshifting preQ1 riboswitch aptamer. This interesting finding may have potential to select compounds with anti-bacteria ability. In sum, we successfully use in trans AONs or metabolites to induce PRF. These findings not only address fundamental mechanism of PRF but have potential to develop drugs against frameshifting diseases or bacteria.UBL - phd migration 201
Modulated Entanglement Evolution Via Correlated Noises
We study entanglement dynamics in the presence of correlated environmental
noises. Specifically, we investigate the quantum entanglement dynamics of two
spins in the presence of correlated classical white noises, deriving Markov
master equation and obtaining explicit solutions for several interesting
classes of initial states including Bell states and X form density matrices. We
show how entanglement can be enhanced or reduced by the correlation between the
two participating noises.Comment: 9 pages, 4 figures. To be published in Quantum Information
Processing, special issue on Quantum Decoherence and Entanglemen
Monitoring ribosomal frameshifting as a platform to screen anti-riboswitch drug candidates
Supramolecular & Biomaterials Chemistr
Local channels preserving maximal entanglement or Schmidt number
Maximal entanglement and Schmidt number play an important role in various
quantum information tasks. In this paper, it is shown that a local channel
preserves maximal entanglement state(MES) or preserves pure states with Schmidt
number ( is a fixed integer) if and only if it is a local unitary
operation.Comment: 10 page
Guided and magnetic self-assembly of tunable magnetoceptive gels
Self-assembly of components into complex functional patterns at microscale is common in nature, and used increasingly in numerous disciplines such as optoelectronics, microfabrication, sensors, tissue engineering and computation. Here, we describe the use of stable radicals to guide the self-assembly of magnetically tunable gels, which we call âmagnetoceptiveâ materials at the scale of hundreds of microns to a millimeter, each can be programmed by shape and composition, into heterogeneous complex structures. Using paramagnetism of free radicals as a driving mechanism, complex heterogeneous structures are built in the magnetic field generated by permanent magnets. The overall magnetic signature of final structure is erased via an antioxidant vitamin E, subsequent to guided self-assembly. We demonstrate unique capabilities of radicals and antioxidants in fabrication of soft systems with heterogeneity in material properties, such as porosity, elastic modulus and mass density; then in bottom-up tissue engineering and finally, levitational and selective assembly of microcomponents
Positive Maps Which Are Not Completely Positive
The concept of the {\em half density matrix} is proposed. It unifies the
quantum states which are described by density matrices and physical processes
which are described by completely positive maps. With the help of the
half-density-matrix representation of Hermitian linear map, we show that every
positive map which is not completely positive is a {\em difference} of two
completely positive maps. A necessary and sufficient condition for a positive
map which is not completely positive is also presented, which is illustrated by
some examples.Comment: 4pages,The Institute of Theoretical Physics, Academia Sinica, Beijing
100080, P.R. Chin
Remote information concentration by GHZ state and by bound entangled state
We compare remote information concentration by a maximally entangled GHZ
state with by an unlockable bound entangled state. We find that the bound
entangled state is as useful as the GHZ state, even do better than the GHZ
state in the context of communication security.Comment: 4 pages,1 figur
An asymptotical von-Neumann measurement strategy for solid-state qubits
A measurement on a macroscopic quantum system does in general not lead to a
projection of the wavefunction in the basis of the detector as predicted by
von-Neumann's postulate. Hence, it is a question of fundametal interest, how
the preferred basis onto which the state is projected is selected out of the
macroscopic Hilbert space of the system. Detector-dominated von-Neumann
measurements are also desirable for both quantum computation and verification
of quantum mechanics on a macroscopic scale. The connection of these questions
to the predictions of the spin-boson modelis outlined. I propose a measurement
strategy, which uses the entanglement of the qubit with a weakly damped
harmonic oscillator. It is shown, that the degree of entanglement controls the
degree of renormalization of the qubit and identify, that this is equivalent to
the degree to which the measurement is detector-dominated. This measurement
very rapidly decoheres the initial state, but the thermalization is slow. The
implementation in Josephson quantum bits is described and it is shown that this
strategy also has practical advantages for the experimental implementation.Comment: 4 pages, 3 figures, accepted for publication as a rapid communication
in Phys. Rev.
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