Implications of adiabatic phases for a vortex in a superconductor film

Based on ideas of off-diagonal long range order and two-fluid model, we demonstrate that adiabatic phases for a slow motion of a vortex in a superconductor film give rise naturally to the Magnus force at finite temperatures.Comment: 6 pages, Late

Universal Existence of Exact Quantum State Transmissions in Interacting Media

We consider an exact state transmission, where a density matrix in one information processor A at time $t=0$ is exactly equal to that in another processor B at a later time. We demonstrate that there always exists a complete set of orthogonal states, which can be employed to perform the exact state transmission. Our result is very general in the sense that it holds for arbitrary media between the two processors and for any time interval. We illustrate our results in terms of models of spin, fermionic and bosonic chains. This complete set can be used as bases to study the perfect state transfer, which is associated with degenerated subspaces of this set of states. Interestingly, this formalism leads to a proposal of perfect state transfer via adiabatic passage, which does not depend on the specific form of the driving Hamiltonian.Comment: 4 pages, no figur

A Numerical Investigation of the Dynamic Wetting Transition on a Moving Substrate

AbstractThe dynamic wetting transition of an interface on a partially wetting substrate is numerically investigated using a diffuse-interface method. Both advancing and receding contact lines are considered. As the driving speed of the substrate exceeds a threshold, the contact line keeps moving with the plate and cannot remain stable. For the receding case, the onset of wetting transition is found to agree with previous lubrication theory, and the transition can be delayed by changing boundary conditions such that the macroscopic meniscus can maintain a pressure difference. For the transition of an advancing contact line, the apparent contact angle remains finite, and the critical speed decreases with the contact angle, which is opposite to the receding case

MITOCHONDRIAL DIVISION: SYNERGIZING IN MITOCHONDRIAL DIVISOME

Mitochondria are the energy factories of the cell. The dynamic nature of cells demands routine changes in mitochondrial morphology by fusion and division. The dynamin GTPase Drp1 is a central mitochondrial division protein, driving constriction of the outer mitochondrial membrane via oligomerization. At least four regulatory factors control Drp1 activity on the outer mitochondrial membrane (OMM): 1) receptor proteins (Mff, MiD49, MiD51, and Fis1); 2) actin filaments; 3) the mitochondrial phospholipid cardiolipin (CL); and 4) Drp1 post-translational modifications, of which two phosphorylation sites (S579 and S600) are the most well studied. However, the molecular mechanism of how these factors work together in Drp1 activation is unknown. In this thesis, I take biochemical and cellular approaches to understand how these regulatory factors work individually and together, showing that: 1) Mff oligomerizes in both solution and cells in a concentration-dependent manner through its C-terminal coiled-coil. The dynamic oligomerization of Mff is crucial for activating Drp1. In the solution, oligomerization-defective Mff fails to activate Drp1 and loses its capacity to recruit Drp1 in U2OS cells. Biochemically, actin filaments work synergistically with Mff to enhance Drp1 activity by reducing the effective concentration of Mff. 2) The activation of MiD49 and MiD51 occurs through long-chain acyl coenzyme A (LCACA), leading to their oligomerization and subsequent activation of DRP1 GTPase activity. A point mutation in the LCACA binding pocket diminishes LCACA binding, resulting in reduced MiD51 oligomerization and impaired Drp1 activation both in solution and HeLa cells. Finally, MiD49 or MiD51 oligomers collaborate with Mff, rather than actin filaments, in DRP1 activation. 3) Phosphorylation at S579 and S600 sites maintain basal GTPase activity, but eliminate GTPase stimulation by actin and decrease GTPase stimulation by cardiolipin, Mff, and MiD49. The oligomerization state of both phospho-mimetic mutants is shifted toward smaller oligomers. Taken together, I propose that mitochondrial division is a multifaceted process involving various factors, and the synergy of these factors may serve distinct purposes for specific mitochondrial division events

Spectral radius, fractional [a,b][a,b]-factor and ID-factor-critical graphs

Let $G$ be a graph and $h: E(G)\rightarrow [0,1]$ be a function. For any two positive integers $a$ and $b$ with $a\leq b$, a fractional $[a,b]$-factor of $G$ with the indicator function $h$ is a spanning subgraph with vertex set $V(G)$ and edge set $E_h$ such that $a\leq\sum_{e\in E_{G}(v)}h(e)\leq b$ for any vertex $v\in V(G)$, where $E_h = \{e\in E(G)|h(e)>0\}$ and E_{G}(v)=\{e\in E(G)| e~\mbox{is incident with}~v~\mbox{in}~G\}. A graph $G$ is ID-factor-critical if for every independent set $I$ of $G$ whose size has the same parity as $|V(G)|$, $G-I$ has a perfect matching. In this paper, we present a tight sufficient condition based on the spectral radius for a graph to contain a fractional $[a,b]$-factor, which extends the result of Wei and Zhang [Discrete Math. 346 (2023) 113269]. Furthermore, we also prove a tight sufficient condition in terms of the spectral radius for a graph with minimum degree $\delta$ to be ID-factor-critical.Comment: 14 pages, 2 figure