Disciplines / Research questions

Physics

691 research topics · 2739 questions

Ultracold atomic chip4 questions
  1. Coherent Y-junction splitting and fragmentation suppression for a guided atom interferometer on a superconducting atom chip

    Open for about 18 years
  2. Continuous quantum degeneracy in a continuously pumped, light-shielded magnetic reservoir of ultracold atoms

    Open for about 11 years
  3. Coherent two-photon microwave transfer and microwave-induced Fano-Feshbach resonances for ultracold sodium on a strong-microwave atom chip

    Open for about 16 years
  4. Origin of the excess phase noise on Ramsey recurrences in a Bose–Einstein condensate interferometer with state-dependent microwave potentials on an atom chip

    Open for about 17 years
High-sensitivity detection technology for ultrasound molecular imaging3 questions
  1. In vivo pharmacokinetics, safety, and generalizability of tetrazine-TCO pretargeted microbubble capture for acute-thrombus ultrasound molecular imaging

    Open for about 9 years
  2. Translating VEGFR2-targeted ultrasound molecular imaging from a transgenic mouse model to early breast cancer detection in women

    Open for about 13 years
  3. Physical Mechanisms of Acoustic Radiation Force–Enhanced Signal Decorrelation of Adherent Targeted Microbubbles and Quantitative Validation of Decorrelation-Weighted Pulse Inversion Contrast Imaging

    Open for about 9 years
Mechanism of Ultrasound Energy and Sonochemistry2 questions
  1. Mechanism of sonoluminescence from highly asymmetric toroidal cavitation-bubble collapse near solid surfaces

    Open for less than 1 year
  2. Do bulk nanobubbles in water spontaneously generate reactive oxygen species?

    Open for about 19 years
Effect of ultrasonic vibration on friction characteristics at contact interfaces5 questions
  1. Quantitative theory of ultrasonic friction-torque reduction in the slow-motion regime: a slowly rotating adhesive micro-contact on an ultrasonically vibrated surface

    Open for about 12 years
  2. Quantitative characterization of surface-acoustic-wave-induced friction suppression in microscopic contacts

    Open for about 26 years
  3. Extending the analytical elastoplastic contact model of longitudinal-vibration friction reduction to real engineering surfaces (asperity interactions, measured height distributions, high-load accuracy, and experimental validation)

    Open for about 6 years
  4. Rough-surface contact mechanics and predictive torque capability for a toothless MEMS traveling-wave ultrasonic micromotor

    Open for about 6 years
  5. Ultrasonic weakening of static friction at amorphous interfaces: microslip versus adhesion mechanisms, effective-temperature constitutive account, and transfer to granular media

    Open for about 13 years
Acoustic cavitation mechanism of ultrasound preparation of nanomaterials4 questions
  1. Mechanism, ambient stability, and functional integration of sonochemically synthesized hydrogenated amorphous silicon nanoparticles from liquid trisilane

    Open for about 9 years
  2. Quantitative mechanism of ultrasonic cavitation-induced deagglomeration: partitioning shock-wave, bubble-cluster-oscillation, streaming, and ultrasonic-capillary contributions

    Open for about 4 years
  3. Acoustic-cavitation-resolving model of ultrasound-intensified reactive mixing in the swirling vortex flow reactor

    Open for about 3 years
  4. Quantitative mechanism, phase-purity window, generality, and scale-up of the ultrasonic-assisted ambient synthesis of surfactant-free colloidal Mn3O4 nanoparticles

    Open for about 20 years
Basic Formulation and Finiteness of Superstring Theory10 questions
  1. Cubic NSNS self-interactions, field redefinitions, and fermionic sectors of the two-field type II superstring field theory

    Open for about 1 year
  2. The on-shell value of the closed string field theory action and its boundary/tadpole completion in noncompact backgrounds

    Open for about 22 years
  3. Completing the linear-dilaton regularization of light-cone gauge superstring amplitudes: extension to heterotic and type I strings, and infrared divergences of the critical limit

    Open for about 7 years
  4. Background independence of closed string field theory beyond marginally connected backgrounds

    Open for about 33 years
  5. Field-redefinition uniqueness and background independence of open-closed superstring field theory

    Open for about 7 years
  6. Rigorous, assumption-free equivalence of the two contour prescriptions in superstring perturbation theory (low spacetime dimensions, stub-free intermediate-state sums, and controlled integral interchanges)

    Open for about 9 years
  7. Completing the linear-dilaton regularization of light-cone gauge superstring field theory: heterotic and Type I amplitudes, and a nonperturbative definition

    Open for about 10 years
  8. Infrared-finite inclusive observables and perturbative unitarity of superstring field theory in four or fewer non-compact dimensions

    Open for about 10 years
  9. Supermoduli-space foundations of closed superstring field theory: the single-cover and canonical picture-changing-insertion problem

    Open for about 12 years
  10. Global background independence of superstring field theory: a formulation valid beyond closely related backgrounds

    Open for about 33 years
The landscape picture of superstring theory10 questions
  1. Controlled realization of maximal-vacuum-energy selection of the weak scale in a UV-complete landscape

    Open for about 7 years
  2. Swampland volume-growth and field-range bounds beyond supersymmetry: deciding the field-excursion-bound vacuum-counting argument

    Open for less than 1 year
  3. Kähler-modulus completion of the universal class of type-IIB flux vacua with analytic mass spectrum: full stabilization within the Large Volume Scenario and stability of the complex-structure sector

    Open for about 5 years
  4. Structure of the exact W=0W=0 flux-vacuum landscape: genericity of level reduction, the Hodge tensor-symmetry correspondence, and point-like vacua

    Open for about 2 years
  5. Uplift-mechanism dependence of the joint statistics of SUSY breaking and the cosmological constant in the string flux landscape

    Open for about 3 years
  6. Does the elliptic Calabi–Yau fourfold Mmax⁡\mathcal{M}_{\max} dominate the F-theory flux-vacuum landscape?

    Open for about 10 years
  7. Compatibility of the integrated Gibbons-Maldacena-Nunez constraint with the four-dimensional trace constraint in brane-uplifted de Sitter vacua of type IIB string theory

    Open for about 10 years
  8. Exploiting and diagnosing sampler-induced structure in the flux landscape at large number of moduli: permutation-aware sampling, the intermediate regime, and the separation of algorithmic bias from landscape structure

    Open for about 3 years
  9. Growth, complexity, and dimensionality of the type IIB/F-theory flux-vacuum locus: the Grimm–Monnee counting conjectures

    Open for about 2 years
  10. The geometric factor in flux-vacuum counting: does moduli-space Euler-density suppression generically overcome flux-ball growth across the Calabi-Yau landscape?

    Open for about 7 years
The Burst Mechanism of Supernova3 questions
  1. Robustness of the progenitor-structure-to-explosion-outcome mapping in calibrated parametrized spherically symmetric core-collapse supernova models (PUSH): calibration transferability, multi-dimensional validation, fallback, rotation, and progenitor uncertainties

    Open for about 8 years
  2. Pulsational delayed detonation of a bound white dwarf after a failed surface detonation: viability and observational outcome of the channel for Type Ia supernovae

    Open for about 32 years
  3. Quantitative multi-dimensional explosion threshold and predictive explosion criterion for neutrino-driven core-collapse supernovae

    Open for about 12 years
Are the supernova remnants the origin of cosmic rays?1 questions
  1. Can supernova-remnant shock acceleration act as a hadronic PeVatron and produce the sharp knee of the cosmic-ray spectrum at 3 PeV?

    Open for about 43 years
First-principles calculation methods beyond LDA5 questions
  1. Making density-corrected DFT trustworthy: predicting when HF-DFT improves results for the right reason, and co-designing functionals with better densities

    Open for about 3 years
  2. Feasible fully screened exchange and the universal reliability of beyond-RPA corrections to the random-phase-approximation correlation functional

    Open for about 19 years
  3. Open development frontiers of the Variational Discrete Action Theory: scalable discrete-action evaluation, unitary sequential product density matrices, a practical DFT+VDAT workflow, and off-shell energy-functional parameterization

    Open for about 5 years
  4. Long-Range Charge-Fluctuation (RPA) Correlation and Size-Extensive Multireference Increments in the Wave-Function Treatment of Bulk Metals

    Open for about 12 years
  5. Surpassing the range-separated hybrid meta-GGA performance ceiling: genuinely nonlocal exchange-correlation functionals for molecular chemistry

    Open for less than 1 year
Magnetization/Particle Number Sector4 questions
  1. Constructive eigenfunction mapping for the one-dimensional charge-pair Hubbard model and the origin of odd-lattice-size level crossings in the Hubbard chain

    Open for about 6 years
  2. Convergence of the Bethe-root series solution of the Heisenberg and XXZ spin chains in a magnetic field

    Open for about 7 years
  3. Ordering of magnetization-sector lowest energies and continuity of the lowest-energy branch at commensurate magnetization in one-dimensional U(1)-symmetric spin chains

    Open for about 11 years
  4. Magnetic structure of antiferromagnetic spin-1 Bose-Hubbard ground states beyond the minimal-total-spin theorem, with continuum contact-interaction and higher-spin extensions

Effective Mechanism for Magnetic Energy Release—Magnetic Reconnection4 questions
  1. Conversion efficiency from flux expelled by a color-spin-locked quark-star phase transition to coherent radio emission

    Open for about 1 year
  2. Fast magnetic reconnection in the magnetorotational-supernova proto-neutron-star core: which mechanism operates, and is it fast enough to matter?

    Open for about 20 years
  3. Does magnetic reconnection limit MRI-driven field amplification in magnetorotational core-collapse supernovae? The unverified reconnection timescale in the proto-neutron-star regime

    Open for about 20 years
  4. Magnetospheric coupling and radiative efficiency of magnetic-flux expulsion from a color-spin-locked quark core: the uncomputed emission mechanism of the CSL fast-radio-burst scenario

    Open for about 1 year
Zero-bias anomalies in tunnelling magnetoresistance in magnetic heterojunctions5 questions
  1. Self-consistent nonequilibrium many-body theory of electron-magnon interaction in realistic three-dimensional magnetic tunnel junctions: reproducing the zero-bias anomaly, finite-bias TMR, and inelastic spin-transfer torque

    Open for about 12 years
  2. Microscopic foundation and experimental validation of the effective-circuit theory for the cusplike zero-bias anomaly in tunneling magnetoresistance

    Open for about 16 years
  3. Origin of the negative zero-bias anomaly and high-energy inelastic features in MgO tunnel junctions with magnetic and nonmagnetic electrodes

    Open for about 16 years
  4. Interfacial magnon excitation and temperature-stable tunnel magnetoresistance in Co2MnSi/MgO magnetic tunnel junctions

    Open for about 18 years
  5. Microscopic origin of the zero-bias anomaly and defect-mediated tunneling statistics in Al2O3-barrier magnetic tunnel junctions

    Open for about 19 years
Subleading eigenvalues and correlation lengths3 questions
  1. Correlation length of the quantum transverse-field Ising model on the Bethe lattice: the bound μ≤1/(q−1)\mu \le 1/(q-1) and the conjectured sharp critical value ξc=1/ln⁡(q−1)\xi_c = 1/\ln(q-1)

    Open for about 18 years
  2. Symmetry-enforced minimal entanglement and minimal correlation length in integer spin-J chains beyond matrix product states

    Open for about 1 year
  3. Exact transfer-matrix spectrum and closed-form ground-state entropy of the Ising antiferromagnet on the Shastry–Sutherland lattice at α=1\alpha=1

    Open for about 45 years
What can the fine structure of Λ\Lambda hypernuclear spectra tell us?2 questions
  1. Quantifying the ΛNN–ΣNN three-body-force effects on the high-lying (³He–d)+Λ continuum states of ⁶_ΛLi within a self-consistent structure-plus-reaction framework

    Open for about 1 year
  2. Dynamical origin of spin-dependent charge-symmetry breaking in the ΛN interaction: the A = 4 mirror hypernuclei ⁴ΛH–⁴ΛHe

    Open for about 53 years
Fermion mass hierarchies and flavor mixing from flavor symmetry7 questions
  1. Dynamical origin of the dominant flavor-symmetric (democratic) quark Yukawa matrix and its compatibility with SO(10)/E6 grand unification

    Open for about 7 years
  2. Completing the disentanglement of fermion mass and flavor-mixing hierarchies: lepton-sector realization and phenomenological closure of the flavor-blind hierarchy framework

    Open for about 10 years
  3. Dynamical origin of the flat (democratic) SO(2)SO(2) flavor structure and its extension to Majorana neutrinos and non-normal orderings

    Open for about 3 years
  4. Completing the modular weighton mechanism for fermion mass hierarchies: weighton vacuum, Kähler and SUSY-breaking corrections, and cosmological viability

    Open for about 6 years
  5. A complete modular flavor model simultaneously preserving the up- and down-sector quark-lepton mass relations

    Open for about 2 years
  6. Complete classification of fermion mass hierarchies near the cusp τ=i∞\tau=\mathrm{i}\infty in modular flavor symmetry models

    Open for about 1 year
  7. Completing the TeV-scale flavor-deconstruction framework: classification, ultraviolet origin, and experimental testability of vector-like-fermion chains for the fermion mass hierarchy

    Open for less than 1 year
Algebraic Bethe ansatz4 questions
  1. Off-shell Bethe vectors beyond the classical Lie series: intrinsic meaning of the uniformizing parameters and extension to exceptional and quantum affine algebras

    Open for less than 1 year
  2. Completeness of the Bethe ansatz for the open XXZ spin chain with non-diagonal boundary terms

    Open for about 23 years
  3. Exact arithmetic of the spin-1/2 XXX Bethe equations: closed-form counting functions, the Pauli principle for Bethe roots, and unphysical singular solutions in the thermodynamic limit

    Open for about 13 years
  4. Completing the nested algebraic Bethe ansatz for rational spin chains with arbitrary simple g\mathfrak{g}-symmetry: the fusion conjecture, unwanted terms, and multi-excitation creation operators

    Open for about 2 years
Hard-square model with diagonal interaction2 questions
  1. Rigorous truncation-error foundations for corner transfer matrix computations of the hard-square lattice gas

  2. Exact solution of the two-dimensional hard-square lattice gas

Manipulation and measurement of individual nanostructures6 questions
  1. Dynamical stability and quantitative Brownian-motion spectroscopy of an optically trapped nanoparticle in superfluid helium

    Open for about 5 years
  2. Quantitative mechanism and predictive design of single-beam three-dimensional optical trapping of plasmonic metal nanowires

    Open for about 13 years
  3. Quantum regime of two Coulomb-coupled nanospheres in a bichromatic optical tweezer: simultaneous ground-state cooling, coherent exchange, and individual addressing

    Open for about 2 years
  4. Quantitative limits of optical-force absorption spectroscopy and quantum-resonant sorting of single nanoparticles

    Open for about 5 years
  5. Microscopic origin and predictive force laws of electron-beam trapping of nanoparticles in liquid cells

    Open for about 13 years
  6. Unresolved metrology and mechanisms in four-point in situ electron-microscopy electromechanical characterization of freestanding metallic and semiconducting nanowires

    Open for about 12 years
Unsolvable boundary of the monomer–dimer problem1 questions
  1. Bulk monomer correlations in the two-dimensional dimer model and the relation between its c=−2c = -2 and c=1c = 1 conformal descriptions

    Open for about 63 years
Optical precision control of single atoms9 questions
  1. Quantum-limited, calibration-free superresolution microscopy of optical fields with a single tweezer-trapped atom

    Open for about 4 years
  2. Metasurface-lens optical tweezers for single neutral atoms: closing the efficiency, chromatic, and scaling gaps to objective-class performance

    Open for about 4 years
  3. Fault-tolerance analysis of single-atom addressing by standing-wave quenching in optical lattices

    Open for about 19 years
  4. Microscopic mechanism of the sharply bias-field-dependent single-atom lifetime in a circularly polarized metalens optical tweezer

    Open for about 1 year
  5. Single-atom trapping, deterministic detection, and control in 3D-printed fiber-lens optical tweezers

    Open for about 4 years
  6. Robustness of SLAP-based single-site addressing of ultracold atoms in optical lattices to spin decoherence, site defects, pump-node imperfections, and photon scattering

    Open for about 13 years
  7. Magnetically insensitive Raman sideband cooling of a single atom to the three-dimensional motional ground state of an optical tweezer

    Open for about 9 years
  8. Full three-dimensional motional ground-state cooling of single atoms in state-dependent optical tweezers via chirp cooling

    Open for about 3 years
  9. Sub-10−410^{-4} site-addressed single-qubit gates for neutral atoms in optical lattices: spontaneous-scattering and beam-misalignment limits

    Open for about 20 years
How do protein chains fold into natural structures?10 questions
  1. Is the folding energy landscape of the B-domain of staphylococcal protein A genuinely multiple-funnelled? Equilibrium weights, force-field robustness, and experimental detection of competing non-native funnels

    Open for about 18 years
  2. Electrostatic control of folding cooperativity in single-domain proteins: mechanism, generality, prediction, and engineering

    Open for about 16 years
  3. Robustness and physical basis of the global effect of point mutations on the site-specific stability and folding of the αtα helix-turn-helix motif

    Open for about 8 years
  4. Mechanistic rules of chaperone-assisted cotranslational folding: how ribosome proximity and trigger factor determine de novo folding pathways at peptide resolution

    Open for about 2 years
  5. General folding-location rules for cotranslational folding of protein domains at the ribosome exit tunnel

    Open for about 11 years
  6. Quantitative, residue-level mechanism of cotranslational protein folding on the ribosome: generality across folds, ribosome–nascent-chain interaction energetics, and chaperone modulation

    Open for about 18 years
  7. Unresolved folding-landscape features of the fast-folding λ-repressor variant λYA near the downhill limit: origin of the minor slow phase, transition-state ensemble composition, possible incipient-downhill subpopulation, and the kinetic prefactor

    Open for about 10 years
  8. Microscopic origin of folding barriers and many-body cooperativity in small single-domain proteins

    Open for about 20 years
  9. Mechanism of the structural-Zn(II)-induced switch from cooperative to partly downhill folding in prokaryotic zinc-finger domains: intermediate structure, metal-binding kinetics, determinants, and generality

    Open for about 13 years
  10. Generality of the foldon-based stepwise pathway model of protein folding

    Open for about 11 years
Equivalence Principle—The Fundamental Principle of Physics6 questions
  1. Improved quantum test of the weak equivalence principle for atoms in coherent superposition of internal energy states

    Open for about 9 years
  2. Foundations and feasibility of torsion-balance tests of the weak equivalence principle for matter in quantum-superposition states

    Open for less than 1 year
  3. Reconciling finite-temperature equivalence-principle violations with the gravitationally coupled Dirac equation for particles and antiparticles

    Open for about 6 years
  4. Does the weak equivalence principle survive full deformed-special-relativity frameworks? Extending the modified-dispersion-relation analysis beyond the one-particle sector

    Open for about 1 year
  5. Tightening Weak Equivalence Principle limits on neutrinos versus photons from blazar timing: controlling intrinsic emission-time offsets and distance uncertainties

    Open for about 38 years
  6. Completing the peculiar-acceleration power-spectrum test of the weak equivalence principle on cosmological scales: sensitivity to realistic violations, relativistic modeling, and observational feasibility

    Open for about 1 year
Low-density phase and high-density phase4 questions
  1. Phase transitions in the Aristoff–Radin lattice model of quasicrystals: rigorous existence, order, and the temperature–chemical-potential phase diagram

  2. Melting density and nature of the fluid-solid transition in the Bowen-Lyons-Radin-Winkler zipper-molecule hard-core model

  3. Hexatic order and two-step melting at large exclusion range in the triangular-lattice k-NN hard-core lattice gas, and the algorithms to reach it

  4. Order of the entropy-driven order-disorder (fluid-crystal) transition in non-sliding hard-core lattice gases

Is the low-energy ionic biological effect caused by direct action?7 questions
  1. Cell-cycle-resolved quantification and validation of the direct-action contribution to mammalian cell killing by ionizing radiation (the DABBLE framework)

    Open for about 5 years
  2. Mechanism of very-low-energy ion-induced DNA damage and mutation: anomalous nitrogen-over-argon effectiveness and unquantified secondary-electron, UV, and X-ray channels

    Open for about 17 years
  3. DNA damage by low-energy ions: species and charge-state scaling, strand-break mechanisms, and hydrated and cellular relevance

    Open for about 17 years
  4. Causal mechanisms of low-energy ion beam mutagenesis in bacteria: quantifying direct energy deposition versus indirect radical chemistry and mechanistically explaining in vivo mutation spectra

    Open for about 19 years
  5. Mechanism of low-keV argon-ion-induced developmental delay in Caenorhabditis elegans larvae: attribution among reactive oxygen species, DNA-damage responses, and cuticle surface damage

    Open for about 15 years
  6. Causal agents, thresholds, and dose-response of mutation induction by plasma immersion low-energy-ion bombardment of naked DNA

    Open for about 16 years
  7. Quantitative mechanism of ultra-low-energy ion-induced DNA strand breaks: direct atomic collisions versus secondary processes

    Open for about 13 years
Absorption and isolation of low-frequency sound waves4 questions
  1. Nonlinear active electroacoustic impedance control beyond the cubic single-degree-of-freedom resonator: multi-degree-of-freedom absorbers and negative-effective-bulk-modulus nonlinear active acoustic metamaterials

    Open for about 7 years
  2. Predictive, as-manufactured modeling of the hybrid perforated-hemispherical-shell and membrane acoustic metamaterial: the unexplained 552 Hz absorption peak and the theory–experiment bandwidth discrepancy

    Open for about 2 years
  3. Unstudied high-frequency sound-insulation peaks of the labyrinth-type Helmholtz–thin-film compound acoustic metamaterial

    Open for about 1 year
  4. Exact simultaneous critical coupling of all resonances in a discrete Helmholtz-resonator array while retaining band-averaged absorption

    Open for about 6 years
Stability of electrorheological and magnetorheological fluids5 questions
  1. Stability–performance tradeoff in zeolite/silicone-oil electrorheological fluids: surfactant and acoustic-stirring stabilization versus retained ER yield stress and response time

    Open for about 13 years
  2. Molecular-scale verification of the binding mechanism between PAA-coated SPIONs and fatty-acid-coated carbonyl iron in bidisperse magnetorheological fluids

    Open for about 6 years
  3. Controlling Factors of Time Instability and the Sedimentation-Performance Trade-off in Ferrofluid-Based Three-Disperse Magnetorheological Fluids

    Open for about 5 years
  4. Long-term durability and lifetime design rules for gel-structured electrorheological materials in shear-mode damping devices

    Open for about 13 years
  5. Sedimentation–redispersibility trade-off in concentrated iron-based magnetorheological fluids: a predictive framework and rational additive design

    Open for about 20 years
Reversible resistance change phenomenon caused by electric pulses4 questions
  1. Quantitative closure of the oxygen-diffusion model for electric-pulse-induced resistance (EPIR) switching in Pr0.7Ca0.3MnO3: direct oxygen-vacancy transport parameters and the mechanism of pulse-enhanced ionic mobility

    Open for about 20 years
  2. Physical origin of the mode-dependent reliability asymmetry between unipolar and bipolar resistive switching in Ag/ZnMn2O4/p+-Si devices

    Open for about 7 years
  3. Microscopic origin and spatial location of electric-pulse-induced resistance switching at a tungsten point contact on an individual ZnO nanotube

    Open for about 16 years
  4. Microscopic origin of the ferroelectric-buffer-enhanced electric-pulse-induced resistance (EPIR) switching in Pr0.7Ca0.3MnO3 films: ferroelectric field effect versus ionic redistribution

    Open for about 19 years
Electron and atomic nucleus scattering4 questions
  1. Constraining the shell-versus-α\alpha-cluster composition of the 12^{12}C and 16^{16}O ground states through density-profile-sensitive elastic scattering

    Open for about 3 years
  2. Validating and correcting the GENIE event generator's quasielastic nuclear models against (e,e'p) reduced cross sections and nuclear transparency

    Open for about 1 year
  3. Simultaneous microscopic description of charge radii and parity-violating asymmetries in 48^{48}Ca and 208^{208}Pb: resolving the CREX–PREX tension and the model dependence of neutron-skin extraction from parity-violating electron scattering

    Open for about 4 years
  4. Charge properties of deformed halo nuclei: deformed relativistic Hartree-Bogoliubov theory in continuum with intrinsic electromagnetic structure corrections

    Open for less than 1 year
Elliptic parametrization of symmetric biquadratic relations2 questions
  1. Degenerate biquadratic regimes for the string-equation Dirichlet problem: John-mapping periodicity, Poncelet dynamics, and the Pell-Abel correspondence

  2. Ladder operators, bispectral algebra, and degenerations of the biorthogonal rational functions on elliptic grids: completing the rational-function analogue of the Askey-Wilson framework

Symmetry and symmetry-breaking mechanisms5 questions
  1. Controlled manipulation of the two symmetry-broken phase states and a first-principles effective model of the driven-dissipative space-time crystal

    Open for about 5 years
  2. Fate of coherent-beam-driven spin symmetry breaking and entropy production in a spinor Bose-Einstein condensate beyond the fully decoherent limit

    Open for about 6 years
  3. Universality class of the continuous Q-QL transition: criticality-enabled U(1) symmetry breaking in 1D spin chains and 1+1D field theory

    Open for about 1 year
  4. Structure, topology, and differential surface tension of inhomogeneous chiral condensates in the chiral limit of QCD from constrained simulations

    Open for about 4 years
  5. Open problems for modulated-symmetry SPT chains: phase transitions, realistic realizations, and bundle-symmetry structure

    Open for about 2 years
Diagonal and non-diagonal integrable boundaries3 questions
  1. Integrable boundary interactions of open SU(4) alternating spin chains: classification beyond the SU(2)×SU(2)-preserving class and higher-rank SU(N) extension

  2. Nested off-diagonal Bethe ansatz for the Dn(1)D_n^{(1)} (so(2n)so(2n)) spin chain with generic non-diagonal open boundaries

  3. Integrable non-factorizable boundaries in doubled-space quantum circuits: classification beyond spin-1/2 free fermions, replica couplings, Bethe-ansatz spectra, and Lindblad form

How exactly do the turbulent fluctuation fields in convective warm clouds affect the formation of large cloud droplets?10 questions
  1. Gelation-time statistics of the sol–gel transition in turbulent droplet collision–coalescence and their link to warm-rain initiation

    Open for about 14 years
  2. Turbulence-modulated collisional growth of cloud droplets toward rain initiation: realistic collision efficiencies, growth-time fluctuations, and the atmospheric Reynolds-number extrapolation

    Open for about 70 years
  3. Do caustic-driven droplet voids and phase-change feedback operate at deep-convective-cloud Reynolds numbers (Rλ∼104R_\lambda \sim 10^4)?

    Open for about 4 years
  4. Turbulent collision-coalescence of cloud droplets: validated parameterizations of the geometric kernel, collision efficiency, Reynolds-number extrapolation, and stochastic-coalescence moment closures for cloud-scale models

    Open for about 20 years
  5. Validation and coupled nonlinear quantification of the tangling-clustering instability as a mechanism of rapid raindrop formation in turbulent stratified atmospheric clouds

    Open for about 12 years
  6. Constraining the turbulent collision–coalescence kernel at cloud Reynolds numbers: the turbulence enhancement of warm-rain autoconversion in precipitating shallow convection

    Open for about 15 years
  7. Open directions in direct Lagrangian simulation of turbulent droplet growth in vertically developing clouds: evolving turbulence, collision–condensation feedback, and microphysical robustness

    Open for less than 1 year
  8. Fate of turbulence-driven continuous growth of cloud droplet size variance by condensation under realistic activation, entrainment, and collision coupling

    Open for about 11 years
  9. Which turbulent collision kernel (Ayala–Wang or Onishi) is realistic at cloud Reynolds numbers?

    Open for about 9 years
  10. Consistent collision efficiencies for quantitative evaluation of turbulence-enhanced droplet collision–coalescence growth at high dissipation rates

    Open for about 8 years
Spectral expansion of multi-point functions4 questions
  1. Do the Matsubara two-particle irreducible vertex divergences persist on the real-frequency axis?

  2. Analytic long-time and long-distance asymptotics of finite-temperature order-parameter correlations in the anisotropic quantum XY chain

  3. Convergence of the form-factor series for the multipoint correlation functions of the 1+1-dimensional sinh-Gordon model

  4. Convergence of form factor expansions in 1+1-dimensional integrable quantum field theories beyond space-like two-point functions of sinh-Gordon

Multi-point joint distribution2 questions
  1. Large-gap asymptotics of the Airy point process on g intervals in the bulk: the Blackstone-Charlier-Lenells genus-g conjecture

  2. Extending the multipoint distribution formula of the KPZ fixed point to arbitrary (non-compactly-supported) upper semicontinuous initial conditions

Physics of multiferroics2 questions
  1. Electric-field switching of out-of-plane polarization in the metallic two-dimensional ferroelectric oxynitride monolayer Tl2NO2 and quantification of magnetoelectric coupling in its WTe2 heterostructure

    Open for about 4 years
  2. Stacking-controlled multiferroicity in bilayer ScI2_2: robustly determining and experimentally realizing the predicted interlayer magnetic switching

    Open for less than 1 year

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