On converse bounds for classical communication over quantum channels

We explore several new converse bounds for classical communication over quantum channels in both the one-shot and asymptotic regimes. First, we show that the Matthews-Wehner meta-converse bound for entanglement-assisted classical communication can be achieved by activated, no-signalling assisted codes, suitably generalizing a result for classical channels. Second, we derive a new efficiently computable meta-converse on the amount of classical information unassisted codes can transmit over a single use of a quantum channel. As applications, we provide a finite resource analysis of classical communication over quantum erasure channels, including the second-order and moderate deviation asymptotics. Third, we explore the asymptotic analogue of our new meta-converse, the $\Upsilon$-information of the channel. We show that its regularization is an upper bound on the classical capacity, which is generally tighter than the entanglement-assisted capacity and other known efficiently computable strong converse bounds. For covariant channels we show that the $\Upsilon$-information is a strong converse bound.Comment: v3: published version; v2: 18 pages, presentation and results improve

Transferability of Coarse-Grained Force Field for <i>n</i>CB Liquid Crystal Systems

In this paper, the transferability of the coarse-grained (CG) force field originally developed for the liquid crystal (LC) molecule 5CB (Zhang et al. J. Phys. Chem. B 2012, 116, 2075−2089) was investigated by its homologues 6CB and 8CB molecules. Note that, to construct the 5CB CG force field, we combined the structure-based and thermodynamic quantities-based methods and at the same time attempted to use several fragment molecular systems to derive the CG nonbonded interaction parameters. The resultant 5CB CG force field exhibits a good transferability to some extent. For example, not only the experimental densities, the local packing of atom groups, and the antiparallel arrangements of nearest neighboring molecules, but also the unique LC mesophases as well as the nematic–isotropic phase transition temperatures of 6CB and 8CB were reproduced. Meanwhile, the limitations of this 5CB CG force field were also observed, such as the phase transition from nematic to smectic was postponed to the lower temperature and the resulting smectic phase structure is single-layer-like instead of partially interdigitated bilayer-like as observed in underlying atomistic model. Apparently, more attention should be paid when applying a CG force field to the state point which is quite different from which the force field is explicitly parametrized for. The origin of the above limitations can be potentially traced back to the inherent simplifications and some approximations often adopted in the creation process of CG force field, for example, choosing symmetric CG potentials which do not explicitly include electrostatic interactions and are parametrized by reproducing the target properties of the specific nematic 5CB phase at 300 K and 1 atm, as well as using soft nonbonded potential and excluding torsion barriers. Moreover, although by construction this CG force field could inevitably incorporate both thermodynamic and local structural information on the nematic 5CB phase, the anisotropic diffusion coefficient ratios for different LC phases in both 6CB and 8CB systems are reproduced well. All these findings suggest that the multiproperty parametrization route together with fragment-based method provides a new approach to maximize the possibility to simultaneously reproduce multiple physical properties of a given molecule or related molecules with similar chemical structures at other state points

Dissipative Particle Dynamics Simulation of the Phase Behavior of T‑Shaped Ternary Amphiphiles Possessing Rodlike Mesogens

We employed dissipative particle dynamics simulations to explore the phase behavior of T-shaped ternary amphiphiles composed of rodlike cores connected by two incompatible end chains and side grafted segments. By fine-tuning the number of terminal and lateral beads, three phase diagrams for the model systems with different terminal chain lengths are constructed in terms of temperature and lateral chain length, which have some common features and mostly compare favorably with experimental studies with the exception a couple of new phases. It is worthwhile to highlight that the mixed cylindrical phase and the perforated layer phase, as the experimentally observed mesophases exclusive for facial amphiphilies, are found in simulations for the first time. Also, a novel gyroid structure is observed in series of T-shaped ternary amphiphiles for the first time. Furthermore, by evaluating the effective volume fraction of lateral chains, the phase sequence spanning from conventional smectic layer phase via perforated layer structures and polygonal cylindrical arrays to novel lamellar mesophase is established, which is not just qualitatively consistent with the related experimental findings but even the stability windows of some mesophases quantitatively correspond well to experimental results. The success of reproducing the in-plane ordering of rods in the lamellar phase as well as the generic phase diagram of such T-shaped ternary amphiphiles in great detail implies that our genetic model qualitatively captures many of the characteristics of the phase behavior of real T-shaped molecules and could serve as a satisfactory basis for further exploration of self-organization in other related soft matter systems

Nanorods with Different Surface Properties in Directing the Compatibilization Behavior and the Morphological Transition of Immiscible Polymer Blends in Both Shear and Shear-Free Conditions

To explore the mechanism of how the nanorod surface properties regulate the compatibilization behavior and the morphology transition in demixing polymer blends, we perform dissipative particle dynamics simulations and study the impact of three typical nanorods on the phase separation kinetics and structure as well as their location and arrangement under both shear-free and shear conditions with the variation of nanorod–polymer affinity parameters. Depending on the dispersion and location of nanorods, blends in the quiescent case either undergo full phase separation and generate bulky two-phase morphology, or experience microphase separation and form BμE-like structure, or proceed viscoelastic phase separation and take the kinetically trapped cocontinuous network morphology, whereas shear flow can either accelerate domain coarsening or strongly impact the phase behavior through shear-induced bulk phase separation or shear-induced ordering transition. Particularly, the shear-induced lamellar phase in Janus nanorod-filled blends chooses parallel orientation and displays the lateral ordering within layers

Coarse-Grained Molecular Dynamics Simulations of the Phase Behavior of the 4-Cyano-4′-pentylbiphenyl Liquid Crystal System

In this paper, with the aim to establish a rational coarse-grained (CG) model for the 4-cyano-4′-pentylbiphenyl (5CB) molecule, we construct three possible CG models (5P, 6P, and 7P) and then determine the bonded and nonbonded interaction parameters separately. For the intramolecular bonded interactions, the bond and angle distributions of the 5CB bulk phase are used as the target properties. For the nonbonded interactions between CG particles, we combine the structure-based and thermodynamic quantities-based methods for the parametrization of CG interaction potentials and attempt to use several fragment molecular systems to derive the CG nonbonded interaction parameters in order to maintain the transferability of our CG models to some extent. Finally, we fix the optimal nonbonded LJ parameters between CG bead pairs such that the results from CG simulations not only correctly reproduce the experimental density and the nematic LC state at 300 K and 1 atm but also reasonably approximate the local structural properties calculated from the underlying atomistic model. Through comparison of the resulting CG data with target properties, the 6P model is found to be the best one among the three, and then we use this model to investigate the phase behavior and dynamic properties. Our results show that the phase transition temperature from nematic to isotropic phase and the diffusion coefficients are reproduced very well, demonstrating the rationality of the 6P model. Our coarse-grained process should have implications for constructing CG models for nCB series or molecules with similar architectures

Additional file 4: Table S3. of Evolution, gene expression profiling and 3D modeling of CSLD proteins in cotton

Comparison of ML and Bayesian trees based on three alignments (Kalign, Mafft and Muscle) using Ktreedist. (DOCX 33 kb

Additional file 14: Table S14. of Evolution, gene expression profiling and 3D modeling of CSLD proteins in cotton

The relative expression level of CSLD genes of G. hirsutum by comparative 2-ΔΔCT method using qRT-PCR. (XLSX 10 kb

Additional file 11: Table S4, 5 and 6. of Evolution, gene expression profiling and 3D modeling of CSLD proteins in cotton

The source of transcriptome data from G. hirsutum, G. arboreum and G. raimondii. (XLSX 12 kb

Additional file 9: Figure S4. of Evolution, gene expression profiling and 3D modeling of CSLD proteins in cotton

Multiple sequence alignments of GrCSLD1, GhCESA1, BcsA and ATCSLD1. The secondary structure of GrCSLD1 was calculated using the DSS algorithm of PyMOL. The violet cylinders, yellow arrows, and black lines indicate the α-helices, β-strand and coil of GrCSLD1; the red rectangles and yellow rectangles indicate the α-helices and β-strand of GhCESA1, and the red lines and yellow lines indicate the α-helices and β-strand of BcsA. The plant-conserved region (P-CR) and class-specific region (CSR) are highlighted with blue and green lines. Large red letters indicate sites of episodic positive selection in GrCSLD1. (TIFF 4834 kb

Additional file 10: Table S15. of Evolution, gene expression profiling and 3D modeling of CSLD proteins in cotton

Model validation scores of the full-length GrCSLD1 protein. (DOCX 22 kb