Disciplines / Research questions
Physics
691 research topics · 2739 questions
Weakly bound nuclei and the continuum3 questions
Self-consistent complex mean field and Berggren completeness for continuum-coupled single-nucleon overlap functions in weakly bound nuclei
Open for about 19 yearsThe low-energy BBe cross section and the near-threshold states of C: constraining the predicted continuum-coupling enhancement
Open for about 3 yearsContinuum coupling of weakly bound states in nuclear lattice effective field theory: from the schematic fixed-dimer three-particle model to the full three-body system
Open for about 6 years
Weak gravitational lensing cosmology6 questions
Systematics-inclusive shear-domain field-level simulation-based inference for Stage-IV weak lensing surveys
Open for less than 1 yearRecovering the initial Gaussian information content of the large-scale structure from weak-lensing observables: higher-order statistics, nonlinear transforms, super-sample modes, and survey design
Open for about 12 yearsCalibrating baryonic effects for Stage-IV cosmic shear: which observables, depths, and systematic controls suffice to recover unbiased cosmological constraints
Open for about 1 yearRobustness of weak-lensing minima and combined peak–minimum statistics for Stage-IV cosmology: joint baryonic-feedback and intrinsic-alignment mitigation
Open for about 6 yearsCalibration of tomographic source redshift distributions and systematics control for cosmic shear constraints on
Open for about 10 yearsOrigin of the anomalous intrinsic-alignment and goodness-of-fit signals in the DECADE NGC weak-lensing data
Open for about 1 year
Triangular lattice Ising model1 questions
Triangular lattice Potts model2 questions
Thermodynamic-limit phase and critical structure of the triangular-lattice -state Potts antiferromagnet and its restricted-solid-on-solid counterpart
Open for about 9 yearsComplex CFTs of the two-dimensional Potts model for and complex : proving the lattice analytic-continuation conjectures
Open for about 8 years
Triangular lattice three-spin model3 questions
Crossover structure and universality along the transition line of the two-dimensional dilute (spin-1) Baxter-Wu model
Open for about 44 yearsTricritical point of the Baxter–Wu model in a transverse magnetic field: location, critical exponents, and universality class
Open for about 12 yearsOpen phase-structure questions for the two-dimensional Baxter–Wu model in a uniform longitudinal magnetic field
Triangular lattice self-dual transformation3 questions
Exact critical surfaces for inhomogeneous bond percolation: the five-bond bow-tie manifold and the exactly solvable class
Open for about 18 yearsExact critical manifold of the five-probability inhomogeneous bow-tie lattice: full-domain proof and rigorous foundation of the negative-probability balancing construction
Open for about 18 yearsOrder and location of the self-dual phase transition in the three-body random-cluster model on the triangular lattice
Open for about 21 years
Thirty-two vertex model3 questions
Necessary and sufficient criterion for reentrant paramagnetic phases in frustrated spin systems
Open for about 38 yearsCompleting the solvability–simulability correspondence between classical spin models and quantum circuits: integrability, approximate solutions, positive Boltzmann weights, and non-unitary circuits
Open for about 18 yearsMonopole-controlled phase structure of exactly solvable 3D quantum vertex models away from the Rokhsar–Kivelson manifold
Unsolved problems of the exact solution of the three-dimensional Ising model2 questions
Rigorous status of the conjectured odd-spin correlation forms underlying the triangular- and cubic-lattice Ising spontaneous magnetization relations
Open for about 5 yearsConserved charges and exact solvability of the three-dimensional Ising model from the twisted tetrahedron equation
Open for about 8 years
Exact solutions of three-dimensional many-body models9 questions
Integrability, excited states, and the role of three-body terms in parent Hamiltonians of Jastrow wavefunctions beyond one dimension
Open for about 5 yearsD-finiteness and exact closed-form representability of the three-dimensional Ising partition function: joint satisfiability of the six necessary conditions
Open for about 82 yearsCompleting the exact-solvability program for the quantum-dilogarithm integrable 3D lattice models of Bazhanov, Kashaev, Mangazeev and Sergeev
Open for less than 1 yearFour-body extension of the exact two-body-T-matrix integral-equation formulation of the Coulomb few-body problem
Open for about 9 yearsOpen analytic problems in the mutual-distance (angle-independent) reduction of the quantum three-body problem: polynomial spectral theory, self-adjointness, and unequal-mass (quasi)-exact solvability
Open for about 9 yearsIntegrability and characterization of three-dimensional lattice models from state-integral solutions of the bicolored tetrahedron equation
Open for less than 1 yearZero-field S=1/2 quantum phase diagram of the pyrochlore-derived 3D Shastry-Sutherland lattice below the exact dimer boundary
Open for about 1 yearExact finite-size Ising partition functions and energy-degeneracy multiplicities for uniform two-dimensional lattices in a field and three-dimensional lattices
Open for about 82 yearsFermionic distance-only eigenstates and completeness of the algebraic spectrum for the quantum three-body problem in the space of relative distances
Open for about 9 years
Three-dimensional correlation function problem2 questions
Solving the exact self-consistency equations of the partial-contraction formulation of the three-dimensional Ising model: constrained correlations, order parameter, and critical exponents
Solving the exact closed self-consistency system for the nearest-neighbour correlations of the three-dimensional Ising model
Three-dimensional local consistency2 questions
Three-dimensional thermodynamic closure problem1 questions
Three-dimensional positive Boltzmann weight problem4 questions
Positive Boltzmann weights and three-dimensional solvable lattice models from Clifford-algebra tetrahedron-equation solutions
Foundations of tetrahedron-equation solutions from state integral models: analytic justification of the degenerate four-parameter limit, the transpose pentagon property, and the relation to other quantum-dilogarithm constructions
Algebraic foundations of the quantum-dilogarithm integrable lattice models in three dimensions: proof of the Zamolodchikov tetrahedron equation, structural characterization, and the quasi-classical circular-lattice limit
Exact solution of the Mangazeev–Bazhanov–Sergeev positive-weight 3D integrable lattice model: convergence of the partition function and rank-size duality of the Bethe Ansatz
Three-sublattice ordering4 questions
Open issues in the singular ferromagnetic susceptibility of the transverse-field Ising antiferromagnet on the triangular lattice
Complete characterization of the -parafermionic multicritical threshold for melting three-sublattice order in triangular-lattice -- Ising antiferromagnets
Universal critical theory of the multicritical point connecting two-step and Potts-Ising melting of three-sublattice order in easy-axis triangular and kagome lattice antiferromagnets
Analytic renormalization-group characterization of the self-dual generalized Baxter-Wu models: marginal-field dependence on coupling asymmetry and the q-dependent electric-charge fugacity
Deletion–contraction relations2 questions
What is the century-old turbulence problem?5 questions
Uniqueness of weak solutions and the equality structure of the turbulent kinetic energy balance for the NS-TKE model
Open for about 12 yearsDo stress-transport turbulence closures give systematic predictive or computational advantages over eddy-viscosity two-equation models in complex flows?
Open for about 21 yearsRigorous dual-stability theory for high-Reynolds-number turbulent flow: explaining moderate adjoint stability factors and guaranteeing output accuracy in CFD
Open for about 22 yearsWell-posedness of the exterior boundary-value problem for RANS equations coupled with two-equation turbulence models
Open for about 5 yearsSymmetry-invariant, regime-general data-driven subgrid-scale stress closures for large-eddy simulation
Open for about 7 years
Percolation limit3 questions
Rigorous exact critical manifolds for inhomogeneous bond percolation: the five-bond bow-tie formula and the scope of multilinear critical surfaces
Exact four-spin correlation functions, cluster-connectivity conformal blocks, and the spin-operator algebra of two-dimensional critical percolation
Open for about 10 yearsRigorous foundations and Q=4 finite-size corrections for the four-point boundary FK-connectivity ratio in the critical two-dimensional Q-state Potts model
Open for about 8 years
Quantitative description of biomolecular evolution10 questions
Can protein-coordination constraints on thermal evolution quantitatively explain the slow macroevolutionary rates of vertebrate body temperature?
Open for less than 1 yearExtending the antibody-library selection-response index to evolvability: quantifying the response to successive cycles of selection and mutation
Open for about 5 yearsMechanistic origins of the information-theoretic signatures of proteome sequence ensembles
Open for less than 1 yearHow much of functional protein sequence space has life on Earth explored?
Open for about 56 yearsThe quantitative mapping from amino-acid physicochemical distances to fitness effects and codon substitution rates, and its domain of validity across selection regimes
Open for about 52 yearsCrossover between neutral and strong-selection scaling of evolutionary path statistics on fitness landscapes
Open for about 11 yearsQuantifying ensemble-induced epistasis and its limit on evolutionary predictability in real proteins
Open for about 8 yearsRobustness and physical grounding of the assembly-theory quantification of selection in natural-product chemical space: mechanistic constraints, database dependence, and the generality of the exploration parameter β
Open for about 2 yearsAre the excess molecular-clock violations in protein-structure evolution driven by positive (diversifying) selection or by relaxation of purifying selection? A calibrated attribution problem
Open for about 7 yearsGeneralizing the integrated life-history model of the protein molecular clock: broader taxa, fossil-calibrated ancestral generation times, and an integrated functional theory of protein evolution
Open for about 1 year
Organization of biomembranes and formation of lipid rafts6 questions
Thermodynamic classification of raft-component co-accumulations in GM1/cholesterol/sphingomyelin membranes: phases, condensed complexes, or nonideal mixing?
Open for about 10 yearsOrdered lipid nanodomains at physiological temperature: do they exist in intact living-cell plasma membranes, and why do they remain nanoscopic?
Open for about 29 yearsMolecular mechanisms of action of small-molecule modulators of lipid raft stability and protein-raft partitioning
Open for about 1 yearFormation mechanism and kinetics of sphingomyelin/cholesterol-associated fluid-disordered nanodomains in nominally homogeneous DOPC/sphingomyelin/cholesterol membranes
Open for about 9 yearsNanoscale structural and mechanistic basis of the lipid raft self-assembly inferred from coupled membrane-phase and lipid-diffusion measurements in living breast cancer cells
Open for about 6 yearsQuantifying lipid scrambling in giant plasma membrane vesicles and identifying the dominant factors of interleaflet coupling in complex asymmetric membranes
Open for about 1 year
Propagation of sound waves in rocks2 questions
Domain of validity of the phonon-momentum mechanism for elastic wave propagation in porous rocks: universality of the damping constant and extension beyond fully saturated Wyllie-type media
Open for about 15 yearsEffective stress coefficients and hydraulic-aperture encoding for elastic-wave signatures of fractured rock
Open for about 5 years
Physical models of sonoporation5 questions
Mechanism and reversibility of microbubble-mediated sonoporation: the membrane-structural basis of transient permeabilization by oscillating ultrasound contrast agents
Open for about 20 yearsQuantitative mechanism and predictive scaling of single-cell membrane poration by tandem-bubble microjets
Open for about 16 yearsGeneralized rupture-regime and damage-threshold map for laser-induced cavitation bubbles interacting with thin elastic membranes
Open for about 11 yearsControlled microbubble oscillation regimes for reproducible threshold-shear-stress sonoporation and the endothelial consequences of microsecond shear stimuli
Open for about 10 yearsExperimental validation and refinement of the wound-and-transport model for site-specific sonoporation: resealing kinetics, nano-pore size distribution, cytoskeletal constraints, and cargo-size-dependent uptake
Open for about 15 years
Acoustic inverse scattering problem7 questions
Rigorous foundation for trace-formula inversion of layered acoustic media with attenuation and nonsmooth profiles
Open for about 18 yearsStability of the multifrequency inverse medium problem in two and three dimensions
Open for about 6 yearsA quantitative regularization theory for the nonsymmetric generalized linear sampling method with limited-aperture scattering data
Open for about 9 yearsCompleting the rigorous high-frequency bridge from inverse Helmholtz scattering with beam (Husimi) data to inverse Liouville scattering for general refractive indices
Open for about 4 yearsSingle-incident-wave uniqueness for inverse scattering by an impedance obstacle (the impedance case of the Schiffer problem)
Open for about 59 yearsRigorous uniqueness, stability, and reconstruction theory for inverse acoustic scattering from multi-frequency sparse backscattering far-field data
Open for about 7 yearsJustified sampling-type reconstruction of a globally (non-locally) rough penetrable interface from near-field scattering data
Open for about 6 years
Stealth mechanism and physical realization of acoustic cloaks5 questions
Robustness and physical realization of Fabry-Pérot-resonance perfect acoustic undetectability
Open for about 8 yearsFinite-mass perfect inertial acoustic cloaking: must exact zero scattering force the inner-boundary density singularity?
Open for about 10 yearsPhysical realization of real-time broadband active acoustic cloaking and illusions in three dimensions
Open for about 5 yearsRealizing the Pendry–Li acoustic metafluid: robust and manufacturable broadband acoustic cloaks from fluid-permeated composites
Open for about 17 yearsShear-wave resonances and the operational bandwidth of acoustic cloaks built from attainable materials
Open for about 16 years
Luminescence mechanism of sonoluminescence7 questions
Dominant light source in single-bubble sonoluminescence: verifying the ionized water-shell radiator, its recombination emission, and nonequilibrium ionization
Open for about 9 yearsMechanism and parameter dependence of the electric-field-affected orange water-molecular emission from acoustic cavitation bubbles in water
Open for about 8 yearsIs single-bubble sonoluminescence attainable as Dicke superradiance? Ultrastrong-coupling feasibility and nonequilibrium cooperative emission in a collapsing bubble
Open for about 28 yearsOrigin of the anomalous near-0.3 μm spectral peak of xenon-bubble single-bubble sonoluminescence and robustness of the radiative-mechanism regime map in water
Open for about 31 yearsExperimental validation of the interfacial-polarization liquid-breakdown mechanism of sonoluminescence: does a collapsing bubble ignite a second, liquid-side light source?
Open for about 18 yearsAnalog-curvature parametric resonance as a sonoluminescence mechanism: first-principles ultraviolet-band spectrum, parameter dependence, and experimental discriminants
Open for about 2 yearsFirst-Principles Ionization Equilibrium and Ionization-Potential Lowering in the Dense Plasma at Sonoluminescence Collapse
Open for about 12 years
Microscopic mechanisms of phonon thermal conductivity and thermal conductivity laws in low-dimensional materials10 questions
Mode-resolved phonon mean free paths and scattering channels in low-dimensional heat conductors: the low-frequency asymptotics of the ballistic-to-diffusive crossover
Open for about 21 yearsDimensional crossover of in-plane thermal transport in few-layer graphene: intrinsic layer-number dependence, structural condition, and quantitative theory
Open for about 16 yearsThe room-temperature phonon hydrodynamic window of graphene: regimes where second-sound heat transport persists against momentum-relaxing scattering
Open for about 11 yearsMechanism by which grain boundaries suppress thermal-conductivity divergence in strained two-dimensional momentum-conserving systems, and the asymptotic behavior of the thermal conductivity of strained pristine graphene
Open for about 1 yearPredictive separation and control of coherent (wave-like) versus incoherent (particle-like) thermal phonon transport in semiconductor nanostructures
Open for about 26 yearsLength Divergence or Convergence of the In-Plane Thermal Conductivity of Suspended Monolayer Graphene beyond ~10 Micrometers
Open for about 12 yearsNonlocal hydrodynamic phonon transport in two-dimensional materials: first-principles validation and experimental observation of the Guyer–Krumhansl phenomenology
Open for about 8 yearsOpen questions in optomechanical thermal-transport measurements of two-dimensional-material monolayers: interface resistance, room-temperature thermodynamics, phonon hydrodynamics, and the size divergence of thermal conductivity
Open for about 7 yearsOrigin and asymptotic limit of the logarithmic length dependence of the thermal conductivity of suspended single-layer graphene
Open for about 12 yearsThe fate of the flexural phonon dispersion and the classification of drifting and driftless second sound in two-dimensional materials
Open for about 18 years
Missing supernova remnants5 questions
The missing nearby supernova remnant: discrete nearby sources and the origin of the local cosmic-ray proton spectrum below 100 TeV
Open for about 20 yearsThe missing Galactic supernova remnants: reconciling the observed radio census of Milky Way supernova remnants with the expected population
Open for about 50 yearsWhat fraction of Galactic forbidden-velocity H I 21-cm wings (FVWs) are old, radio-faded supernova remnants?
Open for about 20 yearsThe missing supernova remnant population of M31: closing the census deficit between about 120 detected remnants and the 320–700 predicted
Open for about 1 yearThe missing supernova remnants of the inner Galactic fourth quadrant: confirming the candidate population and completing the census below previous surface-brightness limits
Open for about 13 years
Experimental detection of time-reversal symmetry — searching for intrinsic atomic electric dipole moments6 questions
Reducing the electronic-structure uncertainties in P- and P,T-violating enhancement factors for LaO, LaS, and LuO
Open for about 2 yearsUnambiguous interpretation of the Hg electric dipole moment limit: the nuclear Schiff moment of Hg and residual experimental systematics
Open for about 38 yearsOpen issues toward an authoritative electric dipole moment measurement of the 129Xe atom and its interpretation via the nuclear Schiff moment
Open for about 42 yearsValidation and completion of the AuX (gold–carbon-group) molecular platform for electron electric dipole moment searches: spectroscopy, spin–orbit loss channels, symmetry-violation sensitivity, and cooling
Open for about 2 yearsQuantitative atomic- and molecular-structure evaluation of the generalized P-, T-, and PT-odd polarizabilities proposed as symmetry-violation observables
Open for about 2 yearsRigorous global extraction of particle-level CP-violating parameters from atomic and molecular EDM experiments: state-of-the-art nuclear structure, extended molecular systems, and the overdetermined measurement set
Open for about 2 years
Is there a unified model describing nuclear structure?5 questions
Grounding the nuclear energy density functional in ab initio calculations: deriving the surface, spin-orbit, and effective-mass terms, a local-density validity criterion, and quantified uncertainties
Open for about 5 yearsOpen problem: converting the demonstrated rooting of the nuclear EDF method in ab initio PGCM-PT with MR-IMSRG-preprocessed Hamiltonians into a practical, error-controlled methodology with mean-field-like cost
Open for about 4 yearsMicroscopic completion and quantitative validity domain of the unified shell–collective–cluster symmetry for multi-shell nuclear excitations
Open for about 12 yearsMicroscopic foundation of the EDF-mapped interacting boson model: origin of the effective cubic three-boson term, configuration-mixing strengths, and boson effective charges
Open for about 13 yearsTurning the nuclear energy density functional method into a proper effective field theory: in-medium power counting and the treatment of self-bound nuclei
Open for about 7 years
The origin of chirality and the nature of chiral catalysis8 questions
Border conditions for spontaneous emergence of chirality in the allylboration of 1,2,3-triazolic aldehydes
Open for about 1 yearActive Species and Quantitative Mechanism of the Soai Asymmetric Autocatalysis: Solution-Phase Speciation of the Pyrimidyl Zinc Alkoxide and the Origin of Enantiomeric-Excess Amplification
Open for about 30 yearsMechanism, Spontaneous Chirality, and Scope of Asymmetric Amplifying Autocatalysis in the Reduction of 3-Acetylpyridine with Dicyclopentylzinc
Open for about 2 yearsAnalytical field theory for the onset of homochirality in the coupled reaction–flocking model of Hoffmann and Giomi
Open for about 3 yearsMechanism of enantiomeric-excess amplification in the Soai reaction: solution speciation of zinc-alkoxide oligomers and its coupling to enantioselective catalysis
Open for about 17 yearsChiral symmetry breaking in large peptide systems: scaling of the abundance–similarity windows and the cooperative-channel mechanism beyond the length-3 truncated model
Open for about 5 yearsQuantitative mechanism, predictive limits, and biomolecular relevance of electrostatics-driven chiral recognition and selection in macroion self-assembly
Open for about 11 yearsExperimental verification of chiral purification at low water activity by hydrophobic-core peptides
Open for about 9 years
Do chiral nuclei exist?5 questions
Onset conditions for static chirality in triaxial nuclei: mapping the boundary between fluctuation-dominated and static-chiral regimes in the A≈100 and A≈130 regions
Open for about 21 yearsQuantal dynamics of multiple chirality in Rh: tunneling, partner-band energy splitting, and the experimental test of the predicted positive-parity chiral band
Open for about 9 yearsUnambiguous identification and characterization of chiral doublet bands in triaxial nuclei: distinguishing static chirality, chiral vibration, and non-chiral alternatives
Open for about 25 yearsγ softness and the stability of nuclear chiral geometry: a quantal, beyond-mean-field theory of chirality in soft triaxial nuclei (the paradigm)
Open for about 19 yearsStatic quadrupole moments of nuclear chiral doublet bands: experimental test and generality of a criterion for distinguishing chiral vibration from static chirality
Open for about 6 years
Chiral Potts model3 questions
The generalized order parameter function of the solvable chiral Potts model for arbitrary rapidities
Establishing the Huse–Fisher chiral universality class of the three-state chiral Potts model with real chirality
Complete finite-size eigenvalue spectrum of the homogeneous N-state chiral Potts transfer matrix beyond the superintegrable point
Chiral Potts order parameter2 questions
Homogeneous and thermodynamic limits of the chiral Potts form-factor determinants: first-principles proof of the order parameter of the general homogeneous chiral Potts model
Finite-separation pair correlations of the integrable chiral Potts model: non-maximal eigenvector overlaps in the superintegrable spectral sum
Chiral Potts free energy3 questions
Commuting Baxter Q-operator and completeness of Bethe equations for the -model in general cyclic representations
Closed form and analytic structure of the generalized order-parameter function of the chiral Potts model for arbitrary rapidities
Modular expansion and arithmetic special values of the chiral Potts integral
Conserved charge completeness1 questions
Bound state poles2 questions
Analytic optimal amplitudes and the unidentified integrable solutions in the two-dimensional charged S-matrix bootstrap
Multi-loop Landau singularities in simply-laced affine Toda theories: completing the Laurent coefficients {a_p, b_p} at higher-order S-matrix poles and proving the network-cancellation mechanism
Characterization and reflectivity of electromagnetic fiber composites5 questions
Validity limits of skin-effect-renormalized homogenization for the microwave dielectric response of conductive-fiber shielding composites
Open for about 10 yearsQuantitative geometry-to-absorption model and the simulation-measurement discrepancy for periodic-hole EVA/polycrystalline-iron-fiber microwave absorbers
Open for about 8 yearsA validated microstructure-to-electromagnetic predictive framework for carbonyl-iron-fiber-filled foam absorbers across centimeter and millimeter waves
Open for about 17 yearsQuantitative separation of Fe4N-interface, particle-size, and packing-density contributions to the electromagnetic response of electrospun Fe@Fe4N/amorphous-carbon submicron-fiber microwave absorbers
Open for about 6 yearsClosed-form design relations and quality criteria for single-layer metal-backed microwave absorbers beyond the narrow-band, normal-incidence reflectivity minimum
Open for about 9 years