The linker histone H1.0 generates epigenetic and functional intratumor heterogeneity

Tumors comprise functionally diverse subpopulations of cells with distinct proliferative potential. Here, we show that dynamic epigenetic states defined by the linker histone H1.0 determine which cells within a tumor can sustain the long-term cancer growth. Numerous cancer types exhibit high inter- and intratumor heterogeneity of H1.0, with H1.0 levels correlating with tumor differentiation status, patient survival, and, at the single-cell level, cancer stem cell markers. Silencing of H1.0 promotes maintenance of self-renewing cells by inducing derepression of megabase-sized gene domains harboring downstream effectors of oncogenic pathways. Self-renewing epigenetic states are not stable, and reexpression of H1.0 in subsets of tumor cells establishes transcriptional programs that restrict cancer cells’ long-term proliferative potential and drive their differentiation. Our results uncover epigenetic determinants of tumor-maintaining cells

Imaging phonon-mediated hydrodynamic flow in WTe2

In the presence of interactions, electrons in condensed-matter systems can behave hydrodynamically, exhibiting phenomena associated with classical fluids, such as vortices and Poiseuille flow. In most conductors, electron-electron interactions are minimized by screening effects, hindering the search for hydrodynamic materials; however, recently, a class of semimetals has been reported to exhibit prominent interactions. Here we study the current flow in the layered semimetal tungsten ditelluride by imaging the local magnetic field using a nitrogen-vacancy defect in a diamond. We image the spatial current profile within three-dimensional tungsten ditelluride and find that it exhibits non-uniform current density, indicating hydrodynamic flow. Our temperature-resolve current profile measurements reveal a non-monotonic temperature dependence, with the strongest hydrodynamic effects at approximately 20 K. We also report ab initio calculations showing that electron-electron interactions are not explained by the Coulomb interaction alone, but are predominantly mediated by phonons. This provides a promising avenue in the search for hydrodynamic flow and prominent electron interactions in high-carrier-density materials.Comment: 11 pages, 4 figures + supplementary materia

Bilinear R-parity violation with flavor symmetry

Bilinear R-parity violation (BRPV) provides the simplest intrinsically supersymmetric neutrino mass generation scheme. While neutrino mixing parameters can be probed in high energy accelerators, they are unfortunately not predicted by the theory. Here we propose a model based on the discrete flavor symmetry $A_4$ with a single R-parity violating parameter, leading to (i) correct Cabbibo mixing given by the Gatto-Sartori-Tonin formula, and a successful unification-like b-tau mass relation, and (ii) a correlation between the lepton mixing angles $\theta_{13}$ and $\theta_{23}$ in agreement with recent neutrino oscillation data, as well as a (nearly) massless neutrino, leading to absence of neutrinoless double beta decay.Comment: 16 pages, 3 figures. Extended version, as published in JHE

Supersymmetric Froggatt-Nielsen Models with Baryon- and Lepton-Number Violation

We systematically investigate the embedding of U(1)_X Froggatt-Nielsen models in (four-dimensional) local supersymmetry. We restrict ourselves to models with a single flavon field. We do not impose a discrete symmetry by hand, e.g. R-parity, baryon-parity or lepton-parity. Thus we determine the order of magnitude of the baryon- and/or lepton violating coupling constants through the Froggatt-Nielsen mechanism. We then scrutinize whether the predicted coupling constants are in accord with weak or GUT scale constraints. Many models turn out to be incompatible.Comment: Final version, references added, minor corrections; LaTeX, 46 page

Electron quantum metamaterials in van der Waals heterostructures

In recent decades, scientists have developed the means to engineer synthetic periodic arrays with feature sizes below the wavelength of light. When such features are appropriately structured, electromagnetic radiation can be manipulated in unusual ways, resulting in optical metamaterials whose function is directly controlled through nanoscale structure. Nature, too, has adopted such techniques -- for example in the unique coloring of butterfly wings -- to manipulate photons as they propagate through nanoscale periodic assemblies. In this Perspective, we highlight the intriguing potential of designer sub-electron wavelength (as well as wavelength-scale) structuring of electronic matter, which affords a new range of synthetic quantum metamaterials with unconventional responses. Driven by experimental developments in stacking atomically layered heterostructures -- e.g., mechanical pick-up/transfer assembly -- atomic scale registrations and structures can be readily tuned over distances smaller than characteristic electronic length-scales (such as electron wavelength, screening length, and electron mean free path). Yet electronic metamaterials promise far richer categories of behavior than those found in conventional optical metamaterial technologies. This is because unlike photons that scarcely interact with each other, electrons in subwavelength structured metamaterials are charged, and strongly interact. As a result, an enormous variety of emergent phenomena can be expected, and radically new classes of interacting quantum metamaterials designed

Fermion Electric Dipole Moments in Supersymmetric Models with R-parity Violation

We analyze the electron and neutron electric dipole moments induced by R-parity violating interactions in supersymmetric models. It is pointed out that dominant contributions can come from one-loop diagrams involving both the bilinear and trilinear R-parity odd couplings, leading to somewhat severe constraints on the products of those couplings.Comment: Revtex, 19pp, four figures in axodraw.st

A Supersymmetric Theory of Flavor and R Parity

We construct a renormalizable, supersymmetric theory of flavor and $R$ parity based on the discrete flavor group $(S_3)^3$. The model can account for all the masses and mixing angles of the Standard Model, while maintaining sufficient squark degeneracy to circumvent the supersymmetric flavor problem. By starting with a simpler set of flavor symmetry breaking fields than we have suggested previously, we construct an economical Froggatt-Nielsen sector that generates the desired elements of the fermion Yukawa matrices. With the particle content above the flavor scale completely specified, we show that all renormalizable $R$-parity-violating interactions involving the ordinary matter fields are forbidden by the flavor symmetry. Thus, $R$ parity arises as an accidental symmetry in our model. Planck-suppressed operators that violate $R$ parity, if present, can be rendered harmless by taking the flavor scale to be $\lesssim 8 \times 10^{10}$ GeV.Comment: 28 pp. LaTeX, 1 Postscript Figur

The magnetic genome of two-dimensional van der Waals materials

Magnetism in two-dimensional (2D) van der Waals (vdW) materials has recently emerged as one of the most promising areas in condensed matter research, with many exciting emerging properties and significant potential for applications ranging from topological magnonics to low-power spintronics, quantum computing, and optical communications. In the brief time after their discovery, 2D magnets have blossomed into a rich area for investigation, where fundamental concepts in magnetism are challenged by the behavior of spins that can develop at the single layer limit. However, much effort is still needed in multiple fronts before 2D magnets can be routinely used for practical implementations. In this comprehensive review, prominent authors with expertise in complementary fields of 2D magnetism (i.e., synthesis, device engineering, magneto-optics, imaging, transport, mechanics, spin excitations, and theory and simulations) have joined together to provide a genome of current knowledge and a guideline for future developments in 2D magnetic materials research