We introduce the Computational 2D Materials Database (C2DB), which organises a variety of structural, thermodynamic, elastic, electronic, magnetic, and optical properties of around 1500 two-dimensional materials distributed over more than 30 different crystal structures. Material properties are systematically calculated by density functional theory and many-body perturbation theory (G 0 W 0 and the Bethe-Salpeter Equation for ∼250 materials) following a semi-automated workflow for maximal consistency and transparency. The C2DB is fully open and can be browsed online at c2db.fysik.dtu.dk or downloaded in its entirety. In this paper, we describe the workflow behind the database, present an overview of the properties and materials currently available, and explore trends and correlations in the data. Moreover, we identify a large number of new potentially synthesisable 2D materials with interesting properties targeting applications within spintronics, (opto-)electronics, and plasmonics. The C2DB offers a comprehensive and easily accessible overview of the rapidly expanding family of 2D materials and forms an ideal platform for computational modeling and design of new 2D materials and van der Waals heterostructures.

We study in detail a variety of gravitational toy models for hyperscaling-violating Lifshitz (hvLif) space-times. These space-times have been recently explored as holographic dual models for condensed matter systems. We start by considering a model of gravity coupled to a massive vector field and a dilaton with a potential. This model supports the full class of hvLif space-times and special attention is given to the particular values of the scaling exponents appearing in certain non-Fermi liquids. We study linearized perturbations in this model, and consider probe fields whose interactions mimic those of the perturbations. The resulting equations of motion for the probe fields are invariant under the Lifshitz scaling. We derive Breitenlohner-Freedman-type bounds for these new probe fields. For the cases of interest the hvLif space-times have curvature invariants that blow up in the UV. We study the problem of constructing models in which the hvLif space-time can have an AdS or Lifshitz UV completion. We also analyze reductions of Schrödinger space-times and reductions of waves on extremal (intersecting) branes, accompanied by transverse space reductions, that are solutions to supergravity-like theories, exploring the allowed parameter range of the hvLif scaling exponents.

We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

A theory of parity-invariant dissipative fluids with q-form symmetry is formulated to first order in a derivative expansion. The fluid is anisotropic with symmetry SO(D − 1 − q) × SO(q) and carries dissolved q-dimensional charged objects that couple to a (q + 1)-form background gauge field. The case q = 1 for which the fluid carries string charge is related to magnetohydrodynamics in D = 4 spacetime dimensions. We identify q+7 parity-even independent transport coefficients at first order in derivatives for q > 1. In particular, compared to the q = 1 case under the assumption of parity and charge conjugation invariance, fluids with q > 1 are characterised by q extra transport coefficients with the physical interpretation of shear viscosity in the SO(q) sector and current resistivities. We discuss certain issues related to the existence of a hydrostatic sector for fluids with higher-form symmetry for any q ≥ 1. We extend these results in order to include an interface separating different fluid phases and study the dispersion relation of capillary waves finding clear signatures of anisotropy. The formalism developed here can be easily adapted to study hydrodynamics with multiple higher-form symmetries.fluid dynamics [4][5][6][7][8][9]; the establishment of a framework for describing interfaces between different fluid phases [10-12]; a new formalism for studying non-relativistic fluids [13][14][15][16]; and the development of hydrodynamic theories with generalised global 1-form symmetries and their connections to magnetohydrodynamics [17][18][19][20] as well as their role in the understanding of effective theories with translational symmetry breaking and states with dynamical defects [21]. This paper introduces a framework for building effective hydrodynamic theories of dissipative fluids with q-form symmetries, generalising previous work for q = 0, 1. These effective theories correspond to the hydrodynamic limit of microscopic descriptions whose underlying fundamental charged objects are q-dimensional (i.e. q-dimensional branes). These q-dimensional objects couple to a background gauge field A q+1 . In the language of [22], these fluids describe microscopic systems with a generalised q-form global symmetry. Associated with the q-form symmetry is a (q + 1)-form current J whose integral over a (D − q − 1) dimensional hypersurface M Γ yields a conserved dipole charge( 1.1) where the operator is the Hodge dual operator in D-dimensional spacetime. This dipole charge counts the number of q-dimensional objects that cross the (D − q − 1)-dimensional hypersurface M Γ . 1 The hydrodynamic theories constructed here capture the collective excitations of these charged q-dimensional objects around a state of thermal equilibrium.

The research program of the TCV tokamak ranges from conventional to advanced-tokamak scenarios and alternative divertor configurations, to exploratory plasmas driven by theoretical insight, exploiting the device’s unique shaping capabilities. Disruption avoidance by real-time locked mode prevention or unlocking with electron-cyclotron resonance heating (ECRH) was thoroughly documented, using magnetic and radiation triggers. Runaway generation with high-Z noble-gas injection and runaway dissipation by subsequent Ne or Ar injection were studied for model validation. The new 1 MW neutral beam injector has expanded the parameter range, now encompassing ELMy H-modes in an ITER-like shape and nearly non-inductive H-mode discharges sustained by electron cyclotron and neutral beam current drive. In the H-mode, the pedestal pressure increases modestly with nitrogen seeding while fueling moves the density pedestal outwards, but the plasma stored energy is largely uncorrelated to either seeding or fueling. High fueling at high triangularity is key to accessing the attractive small edge-localized mode (type-II) regime. Turbulence is reduced in the core at negative triangularity, consistent with increased confinement and in accord with global gyrokinetic simulations. The geodesic acoustic mode, possibly coupled with avalanche events, has been linked with particle flow to the wall in diverted plasmas. Detachment, scrape-off layer transport, and turbulence were studied in L- and H-modes in both standard and alternative configurations (snowflake, super-X, and beyond). The detachment process is caused by power ‘starvation’ reducing the ionization source, with volume recombination playing only a minor role. Partial detachment in the H-mode is obtained with impurity seeding and has shown little dependence on flux expansion in standard single-null geometry. In the attached L-mode phase, increasing the outer connection length reduces the in–out heat-flow asymmetry. A doublet plasma, featuring an internal X-point, was achieved successfully, and a transport barrier was observed in the mantle just outside the internal separatrix. In the near future variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added.