217 research outputs found
Studying the unfolding process of protein G and protein L under physical property space
<p>Abstract</p> <p>Background</p> <p>The studies on protein folding/unfolding indicate that the native state topology is an important determinant of protein folding mechanism. The folding/unfolding behaviors of proteins which have similar topologies have been studied under Cartesian space and the results indicate that some proteins share the similar folding/unfolding characters.</p> <p>Results</p> <p>We construct physical property space with twelve different physical properties. By studying the unfolding process of the protein G and protein L under the property space, we find that the two proteins have the similar unfolding pathways that can be divided into three types and the one which with the umbrella-shape represents the preferred pathway. Moreover, the unfolding simulation time of the two proteins is different and protein L unfolding faster than protein G. Additionally, the distributing area of unfolded state ensemble of protein L is larger than that of protein G.</p> <p>Conclusion</p> <p>Under the physical property space, the protein G and protein L have the similar folding/unfolding behaviors, which agree with the previous results obtained from the studies under Cartesian coordinate space. At the same time, some different unfolding properties can be detected easily, which can not be analyzed under Cartesian coordinate space.</p
Quantum phases of SrCu2(BO3)2 from high-pressure thermodynamics
We report heat capacity measurements of SrCu(BO) under high
pressure along with simulations of relevant quantum spin models and map out the
phase diagram of the material. We find a first-order quantum phase
transition between the low-pressure quantum dimer paramagnet and a phase with
signatures of a plaquette-singlet state below T = K. At higher pressures,
we observe a transition into a previously unknown antiferromagnetic state below
K. Our findings can be explained within the two-dimensional
Shastry-Sutherland quantum spin model supplemented by weak inter-layer
couplings. The possibility to tune SrCu(BO) between the
plaquette-singlet and antiferromagnetic states opens opportunities for
experimental tests of quantum field theories and lattice models involving
fractionalized excitations, emergent symmetries, and gauge fluctuations.Comment: 6 pages + 8 pages supplemental informatio
Local and nonlocal entanglement for quasiparticle pairs induced by Andreev reflection
We investigate local and nonlocal entanglement of particle pairs induced by
direct and crossed Andreev reflections at the interfaces between a
superconductor and two normal conductors. It is shown theoretically that both
local and nonlocal entanglement can be quantified by concurrence and detected
from the violation of a Bell inequality of spin current correlators, which are
determined only by normal reflection and Andreev reflection eigenvalues. There
exists a one-to-one correspondence between the concurrence and the maximal
Bell-CHSH parameter in the tunneling limit
Interference in transport through double barriers in interacting quantum wires
We investigate interference effects of the backscattering current through a
double-barrier structure in an interacting quantum wire attached to
noninteracting leads. Depending on the interaction strength and the location of
the barriers, the backscattering current exhibits different oscillation and
scaling characteristics with the applied voltage in the strong and weak
interaction cases. However, in both cases, the oscillation behaviors of the
backscattering current are mainly determined by the quantum mechanical
interference due to the existence of the double barriers.Comment: 6 pages, 3 fig
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