Disciplines / Research questions

Physics

691 research topics · 2739 questions

Geometric morphology of complex nanostructures and predictions of electronic structures4 questions
  1. Kernel–Surface Decoupling in 58-Electron ~100-Atom Thiolate-Protected Gold Nanoclusters: Mechanism of Surface-Controlled Relaxation from Au103S2(S-Nap)41Au_{103}S_2(S\text{-}Nap)_{41}

    Open for about 9 years
  2. Reliable low-level seeding of nanocluster global-minimum searches: transferable DFTB repulsive refits

    Open for about 5 years
  3. Gibbs-free-energy stability hierarchy of Aln−x_{n-x}Nix_x nanoclusters: systematic isomer search beyond zero-temperature binding energies

    Open for about 5 years
  4. Coupled composition–geometry structure prediction and synthesis-accessible near-UV gap tuning in mixed MgO–ZnO nanoclusters

    Open for about 7 years
Robustness and evolvability of complex biological systems10 questions
  1. Interplay of multiple kinds of robustness with other genotype-phenotype map properties in the evolution of evolvability

    Open for about 2 years
  2. The sign and mechanism of the mutational robustness–evolvability relationship across genotype–phenotype maps

    Open for about 18 years
  3. A general, computationally demonstrated formal definition and measure of robustness and evolvability for genotype-phenotype systems

    Open for about 30 years
  4. Empirical genotype networks of gene regulation: quantifying context and method dependence of binding-site networks and extending exhaustive mapping to whole regulatory circuits

    Open for about 12 years
  5. Empirical validation of the complexity–robustness–evolvability trade-off in natural genotype–phenotype maps, and identification of evolvability-maximizing map architectures

    Open for about 9 years
  6. Conditions under which neutral-network structure in many-to-few genotype-phenotype maps determines phenotypic evolvability and robustness

    Open for about 9 years
  7. A quantitative theory of the evolution of evolvability and its relation to mutational robustness in gene-network genotype-phenotype maps

    Open for about 17 years
  8. Completing the topology-parameter-phenotype map of the yeast TOR signalling circuit and validating its robustness-evolvability organization

    Open for about 15 years
  9. Phenotypic robustness and evolvability, gene-number dependence, and quantitative validation of oscillatory dynamics in experimentally realized synthetic GRN genotype networks

    Open for about 3 years
  10. The phenotype-level robustness–evolvability paradigm beyond RNA: estimating phenotype frequencies, testing generality, and the evolutionary origin of high evolvability

    Open for about 18 years
Non-destructive temperature monitoring during tumor treatment with high-intensity focused ultrasound7 questions
  1. Harmonic-based change in backscattered energy (hCBE) ultrasound thermometry in heterogeneous fat-containing tissue at mid-range frequencies under physiological motion

    Open for about 6 years
  2. In vivo validation of CT Hounsfield-unit thermometry and nadir/hysteresis-based hyperthermic injury detection for HIFU ablation of fatty tissue

    Open for about 12 years
  3. Thermal versus mechanical attribution and tissue-dependent mechanisms of spectral quantitative-ultrasound changes during in-vivo HIFU treatment monitoring

    Open for about 10 years
  4. Generalizing calibrated backscattered-energy ultrasound thermometry (including harmonic CBE) to heterogeneous, perfused in vivo tissue for closed-loop mild hyperthermia

    Open for about 5 years
  5. Uncompensated CBE ultrasound thermometry: a general model of backscatter-energy change during heating, robustness to physiological motion, and calibration with uncertainty bounds for in vivo use

    Open for about 14 years
  6. Experimental validation of speed-of-sound-imaging-guided closed-loop thermostatic HIFU hyperthermia in living tissue

    Open for about 4 years
  7. Deep-learning referenceless PRF-shift MR thermometry in motion-prone organs: extension beyond stationary transcranial targets with temporal-consistency modeling

    Open for less than 1 year
High-genus rapidity curves2 questions
  1. Gauge-theory origin of the chiral Potts model and its higher-genus spectral curve

  2. Single-valued hyperelliptic representation of the invariant order-parameter ratio combination Lpq(r)=Gpq(r) GRq,Rp(r)L_{pq}(r) = G_{pq}(r)\,G_{Rq,Rp}(r) of the N=3N=3 chiral Potts model for arbitrary rapidities

High-genus algebraic curves4 questions
  1. Explicit constants, optimal slope, and limit points for linear realizability of prescribed rational-point counts on curves of every genus over finite fields

  2. Scope and extensions of the Calabi–Yau-to-curve correspondence for Feynman integrals: multi-parameter families and the full four-loop banana integral

  3. Ihara-maximal curves: uniqueness of the genus-7 curve over F7\mathbb{F}_7, and existence of Ihara-maximal curves of genus 19 over F19\mathbb{F}_{19} and genus 24 over F16\mathbb{F}_{16}

  4. Eisenbud–Harris conjecture in Castelnuovo theory: high-genus curves on low-degree surfaces and the hyperplane-section supporting conjecture

Plasma Oscillation and Terahertz Radiation in High-Temperature Superconducting Materials3 questions
  1. Quantum-regime parametric amplification of terahertz Josephson plasma waves: squeezing of the superconducting phase, single-photon THz devices above the millikelvin regime, and control of fluctuating superconductivity

    Open for about 10 years
  2. Experimental realization of terahertz parametric gain reflectivity and a superconductor-based terahertz amplifier in optically driven cuprates

    Open for about 5 years
  3. Composite two-mode resonant state in Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} mesa terahertz emitters: locking mechanism, π/2\pi/2 phase selection, and mode-control conditions

    Open for about 6 years
Mechanism of High-Temperature Superconductivity5 questions
  1. Whether charge-transfer superexchange is the electron-pairing mechanism of cuprate high-temperature superconductors: auditing the Bi2Sr2CaCu2O8+δ Josephson-STM verification and the open components of the mechanism problem

    Open for about 40 years
  2. Quantitative material-specific foundations of polaron-bipolaron superconductivity in cuprates: effective interaction parameters, the BEC-Cooper crossover, and intrinsic pairing symmetry

    Open for about 13 years
  3. Validating the d-density-wave Hartree–Fock account of the cuprate phase diagram: direct DDW detection, glassy domain-wall ground state, gauge-invariant response, and parameter provenance

    Open for about 13 years
  4. Microscopic identification and experimental validation of the hidden fermion driving high-temperature superconductivity and the pseudogap in cuprates

    Open for about 11 years
  5. Microscopic origin of the electronic excitations that set the strength and spatial variation of pairing in Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta}

    Open for about 18 years
Preparation technology for high-temperature superconducting tunnel junctions2 questions
  1. Circuit-layout-uniform ramp formation for high-Tc ramp-edge Josephson junctions: co-optimizing resist reflow, etch-mask thickness, and circuit geometry

    Open for about 19 years
  2. Atomic-scale chemical identity of the interfacial barrier, its formation mechanism, and its link to Josephson properties in La-doped ErBCO/SmBCO ramp-edge junctions

    Open for about 23 years
What is the pairing mechanism of high-temperature superconductors?5 questions
  1. Relating the optically extracted electron-boson coupling function to the critical temperature of high-TcT_c cuprates: d-wave projection with pair-breaking and the underdoped pseudogap regime

    Open for about 17 years
  2. Pairing glue in electron-doped La2−xCexCuO4\mathrm{La}_{2-x}\mathrm{Ce}_x\mathrm{CuO}_4: direct verification of the spin-fluctuation assignment, the origin of the electronic bosonic spectrum, and the T†T^{\dagger} competing order

    Open for about 9 years
  3. Microscopic identification of the electronic bosonic 'glue' and its interplay with phonons in high-Tc cuprate superconductors

    Open for about 14 years
  4. Spin-background-mediated pairing of charge carriers in a two-dimensional doped Mott insulator: microscopic mechanism and finite-density fate

    Open for about 39 years
  5. Glue or no glue: retarded versus unretarded d-wave pairing in the t-J-V model and the screening role of the no-double-occupancy constraint

    Open for about 18 years
Vortex glass phase in high-temperature superconductors7 questions
  1. Static high-field vortex phase of disordered high-Tc superconductors: equilibrium elastic vortex glass or current-induced ordering of a plastically pinned state?

    Open for about 18 years
  2. Validation and transferability of multiharmonic AC-susceptibility fingerprints for identifying the vortex-glass phase in type-II superconductors

    Open for about 18 years
  3. Kinetic arrest versus thermodynamic vortex-glass transition in disordered YBa2Cu3O7−δ: the microscopic origin of the anomalously fragile vortex liquid

    Open for about 19 years
  4. Vortex configurations, oblique-field theory, and glassy phases of an ordered Bose glass: a layered superconductor with a dense periodic triangular columnar-pin lattice

    Open for about 3 years
  5. Asymptotic aging dynamics, effective temperature, and experimental verification of the vortex glass in disordered high-temperature superconductors

    Open for about 20 years
  6. Microscopic origin and ultimate high-field ground state of the exotic vortex states in the quasi-two-dimensional superconductor (TBA⁺)ₓFeSe

    Open for less than 1 year
  7. Nature of the vortex-liquid to vortex-solid transition and vortex-glass critical scaling in highly anisotropic Bi-2223 superconductors

    Open for about 17 years
Opacity of radiation from high-temperature dense materials7 questions
  1. Stark line broadening at stellar-interior conditions and the missing solar opacity

    Open for about 10 years
  2. Validated first-principles radiative opacity of warm dense hydrogen: extending the opacity table beyond the degenerate regime and benchmarking it experimentally

    Open for about 11 years
  3. Experimentally validated first-principles determination of the free-free opacity of aluminum from the cold solid to warm dense matter (15–73 eV)

    Open for about 8 years
  4. Non-LTE-capable super-transition-array modeling of the hot dense germanium buried-layer benchmark: the 1.4-1.9 keV emission disparity, inexpensive non-LTE opacity routes, and the STA/SCO-RCG Planck-mean discrepancy

    Open for about 6 years
  5. Experimental demonstration and theoretical understanding of expansion opacity in laboratory conditions

    Open for about 5 years
  6. Self-consistent free-electron chemical potential in the Starrett–Saumon ion-correlation average-atom model and the magnitude of ion-correlation effects on plasma opacities

    Open for about 7 years
  7. Reducing National Ignition Facility iron x-ray transmission uncertainties to the ±0.02 absolute level required to adjudicate the Z-facility iron-opacity discrepancy at 180–195 eV

    Open for about 9 years
Structure of high-temperature dense materials6 questions
  1. Validity domain of the VAMPIRES variational average-atom model in the strongly coupled, strong-overlap regime of dense plasmas

    Open for about 3 years
  2. Model-independent ion structure and ion-acoustic dynamics of shock-compressed warm dense lithium from inelastic x-ray scattering

    Open for about 17 years
  3. Validated reduced models for the structure and free-electron response of warm dense matter in x-ray Thomson scattering diagnostics

    Open for about 16 years
  4. Ionic structure of warm dense matter in bonding and molecular regimes: the open core of the self-consistent average-atom method

    Open for about 12 years
  5. Quantified-accuracy extension of the average-atom two-component-plasma (AA+TCP) model of warm dense matter to strong ionic coupling

    Open for about 12 years
  6. Unambiguous experimental determination of the ionic static structure factor from elastic x-ray Thomson scattering features in warm dense matter

    Open for about 5 years
Lattice TQTQ relations and CFT QQ operators4 questions
  1. Full 1/N1/N finite-size expansion of the lattice involutive charges of critical lattice models and the generality of the lattice-continuum correspondence of the Baxter Q-operator integrable structure

  2. Completing the lattice-to-CFT fermionic correspondence of the critical XXZ model: all-levels proof of the determinant three-point conjecture, the non-diagonal case, and the second screening family

  3. Sufficiency of the difference and inversion relations for the operator Faddeev equation in the simple Weyl algebra

  4. Completing the BLZ conjectures for quantum KdV monster potentials: degenerate-partition perturbation series and residual completeness regimes

Nonperturbative studies of lattice QCD6 questions
  1. Controlled, fit-free extraction of the phase factor from LLR density-of-states data in finite-density quantum field theory

    Open for about 9 years
  2. First-principles completion of the electroweak radiative correction to semileptonic kaon decays: the full physical-point O(α)O(\alpha) lattice QCD computation and the unknown O(e2p4)O(e^2p^4) chiral contributions to δEMKℓ\delta_{\mathrm{EM}}^{K\ell}

    Open for about 5 years
  3. QCD crossover line and critical endpoint at baryon chemical potentials beyond the reach of analytic continuation (μB≳300\mu_B \gtrsim 300 MeV)

    Open for about 28 years
  4. Out-of-equilibrium chiral magnetic effect in QCD: first-principles determination of the real-time current response to chiral imbalance

    Open for about 14 years
  5. Continuum-limit, large-volume, and strangeness-neutral extensions of direct canonical-ensemble lattice QCD at finite baryon density with physical quark masses

    Open for less than 1 year
  6. Higher-order coefficients, convergence domain, and validation of the T'-expansion scheme for the lattice QCD equation of state at finite baryon chemical potential

    Open for about 5 years
The continuum limit of lattice models3 questions
  1. Conjectured lattice-to-continuum operator identity and spectral classification for the Z2\mathbb{Z}_2-invariant inhomogeneous six-vertex model (Bazhanov–Kotousov–Koval–Lukyanov, 2021)

  2. Conformally covariant scaling limits of energy and spin correlations in non-integrable planar Ising models

  3. Microscopic origin, universality, and deformed correlation functions of the TTˉT\bar{T} deformation on the light-cone lattice

Lattice paths and nonintersecting paths2 questions
  1. Exact evaluation of the O(1) loop-model ground state and the TSSCPP–ASM bijection: closed forms for fully packed loop numbers AπA_\pi and the enumerant Fp,r\mathcal{F}_{p,r}

    Open for about 40 years
  2. The degree of symmetry of tuples of non-crossing lattice paths (watermelons)

    Open for about 6 years
The lattice gas–Ising mapping1 questions
  1. Global isomorphism between the hard-core attractive Yukawa fluid and the Ising lattice gas: exactness, uniqueness of the lattice model, the mapping parameter z, and two-dimensional validation

    Open for about 16 years
Anisotropic Bethe-lattice models2 questions
  1. Finite-temperature extension of the exact hole dynamics in the antiferromagnetic Bethe-lattice tt–JzJ_z model

    Open for about 4 years
  2. Square-lattice phase diagram of semi-flexible self-avoiding trails with independent crossing and collision weights

Anisotropy parameter Δ\Delta3 questions
  1. Edge fluctuations of the melting domain wall in the XXZ spin-1/2 chain at nonzero anisotropy: the Saenz–Tracy–Widom conjecture

    Open for about 4 years
  2. Analytic-in-anisotropy condensed Bethe solutions for the symmetric six-vertex model up to exact half filling

    Open for about 5 years
  3. Non-perturbative arrow correlations of the critical six-vertex model: exact staggered exponents and the Thirring scaling limit beyond small anisotropy

Anisotropic two-dimensional Ising model1 questions
  1. Multiparameter universality for confined weakly anisotropic systems with realistic boundary conditions: anisotropy parameters and the critical Casimir force

    Open for about 2 years
Function-related nonlinear protein conformational changes10 questions
  1. Computing and validating nonlinear transition pathways of alternating-access membrane transporters

    Open for about 2 years
  2. Molecular Mechanism and Generality of Dual-Excitation Nonlinear Light-Intensity Gating in the BLUF Photosensor BlrP1

    Open for about 8 years
  3. Mechanism of voltage sensing and electromechanical coupling in mammalian prestin (SLC26A5): voltage-sensor identity and the functional roles of the evolutionarily remodeled structural elements

    Open for about 25 years
  4. Does the internal conformational state of CFTR control the external electrostatic free-energy landscape that steers cytosolic ATP toward its nucleotide-binding sites?

    Open for about 2 years
  5. Physical validity of the nonlinear elastic-network relaxation scenarios for functional conformational motions in the motor proteins KIF1A and myosin V

    Open for about 16 years
  6. Establishing objective, statistically calibrated criteria for interpreting function-related conformational changes in proteins: the open agenda of Rashin, Rashin and Jernigan (2010)

    Open for about 16 years
  7. Quantitative de-idealization of genericity theorems for binding-induced conformational change and allosteric regulation in proteins

    Open for about 7 years
  8. Physical origin, ligand modulation, and predictive parametrization of sequence-specific residue contact energies in allosteric proteins

    Open for about 15 years
  9. Completing the designed elastic-network machine framework for molecular machines: thermodynamic energetics, prescribed multi-soft-mode design, single-molecule validation, and physical realization

    Open for about 19 years
  10. Open problems of the automaton model of protein dynamics: reconstructing the protein automaton from output data and characterizing the class of protein automata

    Open for about 9 years
Conjugate modulus transformations4 questions
  1. Direct Siegel-style residue-calculus proofs of the modular inversion laws of Jacobi's theta functions ϑ2\vartheta_2 and ϑ4\vartheta_4

  2. Jacobi imaginary transformation counterparts of the mixed-pair circular summation formulas for theta functions (Cai–Bi–Luo Theorems 4 and 5)

  3. A complete algorithmic theory of modular transformations for elliptic Feynman integrals: invariant function classes, fibre transformation matrices, ansatz classification, and analytic boundary-data transport

  4. Analytic completion of the elliptic-integral representation of anisotropic Ising correlations: global validity of the third-kind duality identity, connection constants, and constructive operator factorization

Conformal weights4 questions
  1. Logarithmic T- and Y-systems for the general (r,s)(r,s) Kac boundary conditions of the logarithmic minimal models

  2. Boundary conformal data of the dilute A2(2)A_2^{(2)} loop model at the percolation point: integrable boundary conditions beyond the sine solution and the missing weight 5/965/96

  3. Analytic identification of the scaling-limit boundary conformal field theory of quantum-group-invariant Dn+1(2)D^{(2)}_{n+1} spin chains

  4. Open problems in the lattice regularisation of a non-compact boundary conformal field theory: black-hole brane identification, the lattice-to-continuum map, analytic boundary RG flows, and the free-boundary antiferromagnetic Potts Hamiltonian

Study on atomic coherence effects in solid media3 questions
  1. Full-contrast all-optical coherent population trapping/EIT control and microwave-free sensing with divacancy spin ensembles in silicon carbide

    Open for about 11 years
  2. Quantitative low- and zero-field modeling and mitigation of superhyperfine-induced photon-echo collapse in Er3+^{3+}:Y2_2SiO5_5

    Open for about 6 years
  3. Robust, quantitatively understood, and scalable adiabatic population transfer (STIRAP and bright STIRAP) in rare-earth-ion-doped solids

    Open for about 17 years
Electrically pumped solid-state organic semiconductor lasers4 questions
  1. Validated modeling and experimental verification of the OLED-pumped organic laser diode: threshold, pulsed-to-quasi-CW operation, and modulation-limited data transmission

    Open for about 2 years
  2. Electrically pumped lasing in red-emitting organic semiconductors via TADF-assisted triplet-to-singlet upconversion (the current-injection red organic laser)

    Open for about 5 years
  3. Physical Origin of Current-Driven Spectral Narrowing and the Conditions for Electrically Driven Stimulated Emission in BP3T Single-Crystal Organic Light-Emitting Transistors

    Open for about 17 years
  4. Electrically pumped lasing in organic semiconductors: threshold, modal gain, and conversion efficiency of the single-crystal microcavity OLED platform

    Open for about 30 years
Orbital magnetism of solid materials6 questions
  1. Quantitative ab initio prediction of current-induced orbital magnetization (the orbital Edelstein effect) in noncentrosymmetric materials

    Open for about 5 years
  2. Microscopic origin and quantitative spectroscopic theory of the large unquenched V3+^{3+} orbital moment in the van der Waals ferromagnet VI3_3

    Open for about 3 years
  3. Localized versus itinerant orbital magnetization in crystals: first-principles evaluation and magneto-optical extraction of the self-rotation and itinerant-circulation decomposition

    Open for about 18 years
  4. Topological orbital ferromagnetism in γ-FeMn beyond the virtual-crystal approximation: disorder-inclusive theory, chirality expansion of the Hall response, inverse effects, and experimental detection

    Open for about 9 years
  5. Giant unquenched orbital moments in two-dimensional magnets: robust first-principles prediction and materials discovery beyond octahedral coordination, up to the Lz=2ℏL_z=2\hbar quantum

    Open for about 1 year
  6. Measurability and density-functional incorporation of the large nonlocal (itinerant) contributions to orbital magnetization in ferromagnetic insulating perovskite transition-metal oxides

    Open for about 12 years
Inertial Confinement Fusion Ignition and Supernova Explosion9 questions
  1. The 56^{56}Ni problem in core-collapse supernova explosions: testing the neutrino-driven mechanism against observed nickel masses, from Type II to stripped-envelope supernovae

    Open for about 9 years
  2. Extending the Hamiltonian thin-shell theory of Rayleigh–Taylor degradation of ICF implosion performance: 3D asymmetries, the acceleration/ablation phase, and ignition-coupled hot-spot dynamics

    Open for about 1 year
  3. A general predictive theory of Rayleigh–Taylor instability growth and its transition to turbulent mixing at converging interfaces

    Open for about 72 years
  4. Generality and limits of hydrodynamic scale invariance in laser-driven high-energy-density implosion experiments

    Open for about 6 years
  5. Feasibility of the double-cone ignition scheme for inertial confinement fusion under full multi-dimensional physics and integrated experimental demonstration

    Open for about 5 years
  6. Final explosion energies and robustness of delayed, SASI-aided neutrino-driven core-collapse supernova explosions

    Open for about 19 years
  7. Final outcomes of high-compactness core-collapse supernova progenitors after shock revival: successful explosions, fallback, and black-hole formation

    Open for about 15 years
  8. Definitive first-principles prediction of core-collapse supernova outcomes in three-dimensional general relativity with full Boltzmann neutrino transport

    Open for about 14 years
  9. Robustness of the experimentally inferable inertial confinement fusion ignition threshold fα≃1.4f_{\alpha}\simeq 1.4 under operational definitions and highly distorted implosions

    Open for about 7 years
Propagation characteristics of light waves at metal-based interfaces4 questions
  1. Microscopic origin, unbiased measurement, and predictive control of grain-boundary scattering losses of surface plasmon polaritons in polycrystalline gold films

    Open for about 17 years
  2. Highly confined ultraviolet surface plasmon polaritons on nanostructured metal interfaces: interface-topology design, low-loss material screening, and experimental realization

    Open for about 8 years
  3. Realistic-loss, fabrication-tolerance, and bandwidth limits of gradient-refractive-index-medium plasmonic bends and adapters at visible wavelengths

    Open for about 9 years
  4. Validated modal description of surface plasmon polaritons at the planar interface of a metal and an ambichiral nanostructured medium

    Open for about 12 years
Spectral invariance and polarization invariance in light propagation4 questions
  1. Spectral-density and polarization propagation laws for stochastic electromagnetic beams beyond linear, deterministic, z-uniform paraxial gain/absorbing media

    Open for less than 1 year
  2. Classification of (3+1)D propagation-invariant space-time wave packets in free space: extension of the 10-class scheme and emergence of new classes

    Open for about 7 years
  3. Broadband extension of the cross-spectral purity reduction formulas for intensity-normalized coherence Stokes parameters of nonstationary electromagnetic beams

    Open for about 3 years
  4. Purity of partial polarization for nonparaxial and broadband electromagnetic fields: invariance conditions

    Open for about 13 years
The question of the nature of light5 questions
  1. Extending the photon wave function formalism to lossy, bounded, and spatially nonlocal media

    Open for about 10 years
  2. Quantum-controlled settings in Bell-inequality experiments: formulation, statistical signatures, and no-go consequences of extending the quantum delayed-choice framework

    Open for about 15 years
  3. Weyl–Wigner–Moyal phase-space formalism for the photon built on the momentum and the commuting position operators (p⃗^,X⃗^)(\hat{\vec{p}},\hat{\vec{X}})

    Open for about 6 years
  4. Experimental verification and generalization of the geometric-phase–which-path complementarity relation of the photon

    Open for about 2 years
  5. Breaking the plasma-photon-mass degeneracy in fast radio burst dispersion to constrain the photon rest mass

    Open for about 10 years
The first calibration standard in optoelectronic device testing2 questions
  1. Reducing the mechanical-attenuator calibration uncertainty to ≤0.1% in the 1 mW dissemination chain of the State Working Standard of average optical power (dissemination directly from the primary standard GET 170-2011)

    Open for about 10 years
  2. Realizing the optical watt by radiation pressure: laser power metrology from below a few watts to the kilogram-independent 100 kW regime at cryogenic-radiometer-level uncertainty

    Open for about 7 years
Quantum states of cold atoms in optical superlattices10 questions
  1. Robustness, decoherence, and scaling of AC-drive-controlled atom movement and entanglement on an optical superlattice: the untested performance envelope of the Zhang–Yang (2019) protocol

    Open for about 6 years
  2. Experimental realization of chiral magnetic dynamics of the massive Schwinger model with ultracold fermions in an optical superlattice

    Open for less than 1 year
  3. Interaction-induced pair superfluid of bosonic atoms in optical superlattices: thermodynamic-limit pair-correlator exponent, universality classes, phase boundaries, and stability beyond one dimension

    Open for about 19 years
  4. Local relaxation of the density-wave quench in the one-dimensional Bose-Hubbard model at finite interaction: Gibbs versus generalized Gibbs ensemble, the effective-temperature map, and the long-time momentum distribution

    Open for about 18 years
  5. Validity and extensions of three-dimensional atom localization in the polychromatic optical superlattice

    Open for about 15 years
  6. Interaction effects and correlated fractional quantum Hall phases in synthetic-magnetic-field optical lattices

    Open for about 22 years
  7. Trap effects on the quantum phases and correlation signatures of ultracold bosons in a two-dimensional optical superlattice

    Open for about 19 years
  8. Localization mechanisms in a finite harmonically confined optical superlattice: topological classification beyond trap dominance and parameter-general dynamical readout

    Open for less than 1 year
  9. Experimental identification of interwell coherence and off-diagonal correlations in the superfluid-Mott-insulator transition of a one-dimensional optical lattice with double-well confinement

    Open for about 19 years
  10. Defect-production scaling for linear quenches across an extended gapless superfluid region in the one-dimensional superlattice Bose-Hubbard model

    Open for about 10 years
Optical clocks: defining the second with light6 questions
  1. Completing the specification of an ensemble (multi-transition) definition of the SI second

    Open for about 6 years
  2. Closed-loop conditions for squeezing-enhanced optical atomic clocks: anti-squeezing, alternative protocols, and dead-time-free multi-ensemble architectures

    Open for about 6 years
  3. Mid-10−2010^{-20} systematic uncertainty for the 176Lu+^{176}\mathrm{Lu}^+ optical clock and inter-institute validation of optical-clock accuracy

    Open for less than 1 year
  4. Correlated reference standards, adaptive weighting, and multi-laboratory extension for realizing an SI second defined by the geometric mean of multiple clock transitions

    Open for less than 1 year
  5. Routine entanglement-enhanced optical clock operation below the standard quantum limit, and scaling entanglement-enhanced comparisons to independent clocks

    Open for about 3 years
  6. Pushing optical lattice clock systematic uncertainty below 10−1910^{-19}: blackbody-radiation shift control, dynamic-correction modeling, collective radiative effects, and tunneling at shallow lattice depth

    Open for about 2 years
Do photons have rest mass?5 questions
  1. Robust photon-mass bound from Schumann resonances with realistic ionospheric modeling

    Open for about 55 years
  2. Which assumption must fail: reconciling a non-zero photon mass with observed TEM propagation in coaxial cables

    Open for about 3 years
  3. Photon-mass reach of solar-system Shapiro time delays: full orbit-determination re-fit with a free photon mass and quantified sensitivity limits

    Open for about 2 years
  4. Extending the pulsar spin-down bound on the photon mass beyond AR Scorpii toward the 10−5110^{-51} g regime

    Open for about 9 years
  5. Vortex neutralization of the Proca field in Higgs-mechanism photon mass: vortex-network cosmology, primordial magnetogenesis, and the survival of astrophysical photon-mass bounds

    Open for about 23 years
Experimental Testing of the Equivalence Principle in General Relativity5 questions
  1. Disentangling composition-dependent weak-equivalence-principle violation from distance-dependent effective Earth gravity in satellite laser-ranging tests

    Open for about 7 years
  2. Testing the weak equivalence principle with an entangled two-species test mass: predicting and measuring whether entanglement affects free fall

    Open for about 8 years
  3. Quantum-clock tests of the equivalence principle beyond the de Broglie-gauge phase, and the extension to active-gravity regimes in matter-wave interferometry

    Open for about 11 years
  4. Controlling propagation and gravitational-potential systematics in polarimetric tests of the Einstein equivalence principle: from upper limits on Δγp\Delta\gamma_p to a systematics-controlled, theory-discriminating measurement

    Open for about 6 years
  5. Improving laboratory sensitivity to short-range equivalence-principle-violating interactions: beyond the Rot-Wash floor

    Open for about 26 years
Orbital Diffusion and Solar System Stability10 questions
  1. From resonance-web statistics to a quantitative theory of chaos in the inner Solar System

    Open for about 4 years
  2. Anomalous diffusion exponents in Solar System chaotic transport: dynamical origin and genericity

    Open for about 4 years
  3. First-principles stochastic theory of the chaotic destabilization of the inner Solar System

    Open for about 5 years
  4. Determining the actual chaoticity of the outer Solar System and the origin of its fine-scale dynamical structure

    Open for about 19 years
  5. Dynamical origin of Mercury's subdiffusive secular evolution: why the secular eigenfrequency g1g_1 subdiffuses, why its boundaries are asymmetric, and what produces intermittency

    Open for about 3 years
  6. Calibrating the probability of destabilization of the inner Solar System within 5 Gyr, and the conditional risk of a planetary collision with Earth

    Open for about 17 years
  7. Dynamical mechanism and generality of one-dimensional advection–diffusion in the long-term chaotic evolution of planetary systems

    Open for about 3 years
  8. Statistical convergence of long-term N-body simulations beyond the secular Solar System: minimum timesteps for resonant planetary architectures

    Open for about 1 year
  9. Converged, validated, and physically interpretable long-term instability statistics for the Solar System

    Open for about 18 years
  10. A quantitative theory linking quasi-integral diffusion to the instability times of the inner Solar System

    Open for about 3 years

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