Ultraviolet Cutoff Research Articles

NaB3O4F(OH): A Hydroxyfluorooxoborate with One-Dimensional Chain Featuring Large Birefringence and Short Ultraviolet Cutoff Edge.

A new sodium hydroxyfluorooxoborate, NaB3O4F(OH) (NBOFH), was discovered and synthesized. NBOFH features the unprecedented [B3O4F(OH)] infinite chain constructed by the novel fundamental building block (FBB) of [B3O5F(OH)]. NBOFH has a large birefringence of 0.097 at 1064 nm and short ultraviolet (UV) cutoff edge below 200 nm. First-principles calculations and response electron distribution anisotropy (REDA) were performed to explain the structure-property relationships. This work provides a novel strategy for the synthesis of deep-ultraviolet birefringent crystals and enriches the structural diversity of the emerging hydroxyfluorooxoborates.

Perturbative calculations of deuteron form factors

We calculate the deuteron charge, electric quadrupole, and magnetic form factors up to next-to-next-to-leading order in chiral effective field theory, treating subleading corrections, especially that of chiral nuclear forces, in perturbation theory. We examine the power counting based on naive dimensional analysis by investigating the ultraviolet cutoff variation of these form factors. We find that the N${}^2$LO magnetic form factor shows significant cutoff dependence, suggesting the contact current operator responsible be enhanced. After promotion to N${}^2$LO, it indeed renormalizes the magnetic form factor. This is in agreement with a previous work based on renormalization-group analysis. For the charge and quadrupole moments, perturbative calculation allows us to study how they scale with multiple low-energy parameters such as the pion mass, deuteron binding momentum, and momentum transfer.

C(NH2)3]2Zn(CO3)2: A Guanidinium-Templated Ultraviolet Nonlinear Optical Material.

A novel guanidinium-templated ultraviolet (UV) nonlinear optical zinc carbonate crystal, [C(NH2)3]2Zn(CO3)2 (GZCO), has been synthesized in a closed system at low temperatures. GZCO crystallizing in the tetragonal noncentrosymmetric nonpolar space group, P41212 exhibits a three-dimensional anionic framework constructed by interconnected [Zn6C6O32] 12-membered ring channels with inorganic CO3 triangles and ZnO4 tetrahedra. Notably, the anhydrous GZCO shows a very high thermal stability among guanidine-based hybrid NLO materials benefiting from the confinement effect of the organic cations within inorganic channels. The UV-visible transmittance spectrum reveals that GZCO has a short UV cutoff edge of 210 nm, corresponding to the large band gap of 5.9 eV. GZCO exhibits a mild second-harmonic generation efficiency of 0.5 × KH2PO4 with type-I phase-matching behavior.

NH4IO2F2 and (NH4)3(IO2F2)3·H2O: A Series of Ammonium-Containing Fluoroiodates with Wide Band Gaps.

A series of ammonium-containing fluoroiodates, NH4IO2F2 and (NH4)3(IO2F2)3·H2O, with isolated [IO2F2] units have been fabricated by a fluorine-oxygen substitution strategy from NH4IO3. The two compounds crystallize in the orthorhombic system, but in different space groups, noncentrosymmetric Pca21 for NH4IO2F2 and centrosymmetric Pnma for (NH4)3(IO2F2)3·H2O, and show wide band gaps of 4.53 eV for (NH4IO2F2) and 4.55 eV for ((NH4)3(IO2F2)3·H2O). In addition, NH4IO2F2 exhibits a 1.2 × KDP second harmonic generation response, a short ultraviolet cutoff edge in iodates, and a good crystal growth habit. The crystal of NH4IO2F2 with a size of 11 × 5 × 2 mm3 was obtained by the aqueous solution method. The results enrich the structural diversity of iodate and supply a greater understanding of the design of new functional materials based on the fluoroiodates.

Central limit theorem for Gibbs measures on path spaces including long range and singular interactions and homogenization of the stochastic heat equation

We consider a class of Gibbs measures defined with respect to increments {ω(t)−ω(s)}s<t of d-dimensional Wiener measure, with the underlying Hamiltonian carrying interactions of the form H(t−s,ω(t)−ω(s)) that are invariant under uniform translations of paths. In such interactions, we allow long-range dependence in the time variable (including power law decay up to t↦(1+t)−(2+ε) for ε>0) and unbounded (singular) interactions (including singularities of the form x↦1/|x|p in d≥3 or x↦δ0(x) in d=1) attached to the space variables. These assumptions on the interaction seem to be sharp and cover quantum mechanical models like the Nelson model and the polaron problem with ultraviolet cut off (both carrying bounded spatial interactions with power law decay in time) as well as the Fröhlich polaron with a short range interaction in time but carrying Coulomb singularity in space. In this set up, we develop a unified approach for proving a central limit theorem for the rescaled process of increments for any coupling parameter and obtain an explicit expression for the limiting variance, which is strictly positive. As a further application, we study the solution of the multiplicative-noise stochastic heat equation in spatial dimensions d≥3. When the noise is mollified both in time and space, we show that the averages of the diffusively rescaled solutions converge pointwise to the solution of a diffusion equation whose coefficients are homogenized in this limit.

Scalar Čerenkov radiation from high-energy cosmic rays

As first noted by Robert Wagoner in the 1970s, if a scalar field is nonminimally coupled to the Ricci scalar and propagates at subluminal speeds, then there exists the possibility of scalar $\check{\hbox{C}}$erenkov radiation from a moving particle. The mere observation of high-energy cosmic rays could in principle rule out the existence of such scalar fields since any particle moving faster than scalar perturbations would lose energy in the form of scalar waves until it moves slower than those. We compute in detail the energy loss to scalar waves and find that it scales with the square of the ultra-violet (UV) cutoff frequency of the effective field theory (EFT) of gravity. For dark-energy-motivated EFTs, the UV cutoff can be low, in which case that energy loss could always be negligible. In contrast, if viewed as a covariant theory valid at all scales or as an EFT valid at higher energies, perhaps even all the way up to the Planck scale, as may be the case if motivated by quantum-gravity perspectives, then the energy loss to scalar waves may diverge or become dramatically large. In this case, high-energy cosmic rays of extragalactic origin stringently constrain any conformally coupled scalar fields with non-canonical kinetic terms, although a minimum scalar phase velocity is required to trust the EFT.

Dynamical dark energy and infinite statistics

In the [Formula: see text]CDM model, dark energy is viewed as a constant vacuum energy density, the cosmological constant in the Einstein–Hilbert action. This assumption can be relaxed in various models that introduce a dynamical dark energy. In this paper, we argue that the mixing between infrared (IR) and ultraviolet (UV) degrees of freedom in quantum gravity leads to infinite statistics, the unique statistics consistent with Lorentz invariance in the presence of nonlocality, and yields a fine structure for dark energy. Introducing IR and UV cutoffs into the quantum gravity action, we deduce the form of [Formula: see text] as a function of redshift and translate this to the behavior of the Hubble parameter.

Enhancement of Birefringence in Borophosphate Pushing Phase-Matching into the Short-Wavelength Region.

Borophosphates are very known for the short ultraviolet (UV) cutoff edge and have become the promising UV and deep-UV functional crystals candidates; however, tetrahedral [PO4] and [BO4] groups own weak anisotropy of polarizability and are not conducive to large birefringence, which hinders their application in the short-wavelength region. Improving their birefringence without compromising the band gap is the main research objective. By introducing the excellent birefringent functional groups, such as [B2O5], [BO2]∞ chain, [B2Ox(OH)5-x], and so forth into borophosphates, seven borophosphates with improved birefringence were successfully synthesized (Δn > 0.05@532 nm). Remarkably, among them, the centimeter-sized crystal of Rb3B8PO16 with a short deep-UV cutoff edge (175 nm) and large birefringence (Δn(exp.) ∼ 0.072@589.3 nm) exhibits the shortest phase-matching wavelength (222 nm), which makes Rb3B8PO16 a promising UV NLO crystal, while KB6PO10(OH)4 with deep-UV cutoff edge features the largest birefringence (Δn(exp.) ∼ 0.103@546 nm) in the reported borophosphate system, making KB6PO10(OH)4 a promising deep-UV birefringent crystal. This study not only provides feasible strategies for increasing the birefringence of borophosphates but also pushes phase-matching into the short-wavelength region.

The spatial Functional Renormalization Group and Hadamard states on cosmological spacetimes

A spatial variant of the Functional Renormalization Group (FRG) is introduced on (Lorentzian signature) globally hyperbolic spacetimes. Through its perturbative expansion it is argued that such a FRG must inevitably be state dependent and that it should be based on a Hadamard state. A concrete implementation is presented for scalar quantum fields on flat Friedmann-Lemaître spacetimes. The universal ultraviolet behavior of Hadamard states allows the flow to be matched to the one-loop renormalized flow (where strict removal of the ultraviolet cutoff requires a tower of potentials, one for each power of the Ricci scalar). The state-dependent infrared behavior of the flow is investigated for States of Low Energy, which are Hadamard states deemed to be viable vacua for a pre-inflationary period. A simple time-dependent infrared fixed point equation (resembling that in Minkowski space) arises for any scale factor, with analytically computable corrections coding the non-perturbative ramifications of the Hadamard property in the infrared.

Temperature Dependence of Optical Couplant Grease Transmission at UV and Visible Wavelengths

Optical couplant greases based on polydimethylsiloxane (PDMS) may be employed in devices such as scintillator-based radiation detectors that operate in extreme environmental conditions. The optical transmission of Dow Corning DOWSIL Q2-3067 optical couplant grease was measured at room temperature as a function of wavelength (200&#x2013;800 nm) and grease thickness (0.13&#x2013;1 mm). Across the spectral range, transmission decreased with increasing thickness, and the increase was more pronounced at wavelengths &#x003C; 400 nm. An effective ultraviolet (UV) cutoff wavelength of &#x007E;270 nm was found, independent of grease thickness, although a weak transmission feature was observed below this cutoff at 233 nm. The optical transmission spectra exhibited a dependence on temperature, increasing with increasing temperature to 50 &#x00B0;C and decreasing with decreasing temperature to &#x2212;10 &#x00B0;C. This temperature dependence was more pronounced at wavelengths &#x003C; 400 nm and for thicker grease layers. Below &#x2212;10 &#x00B0;C, transmission decreased sharply for all wavelengths. This decrease was correlated with a sharp increase in viscosity, indicating that the grease undergoes a thermal transition at &#x2212;11 &#x00B0;C &#x00B1; 1 &#x00B0;C. This thermal transition occurs more slowly with decreasing temperature for thinner layers of grease, but all measured grease thicknesses were reasonably opaque at temperatures below &#x2212;20 &#x00B0;C. These results will aid in predicting the optical and mechanical performance of optical systems such as radiation detectors exposed to extreme outdoor environmental conditions.

On the Ultraviolet Limit of the Pauli–Fierz Hamiltonian in the Lieb–Loss Model

Two decades ago, Lieb and Loss (Self-energy of electrons in non-perturbative QED. Preprint arXiv:math-ph/9908020 and mp-arc #99–305, 1999) approximated the ground state energy of a free, nonrelativistic electron coupled to the quantized radiation field by the infimum E_{alpha , Lambda } of all expectation values langle phi _{el} otimes psi _{ph} | H_{alpha , Lambda } (phi _{el} otimes psi _{ph}) rangle , where H_{alpha , Lambda } is the corresponding Hamiltonian with fine structure constant alpha >0 and ultraviolet cutoff Lambda < infty , and phi _{el} and psi _{ph} are normalized electron and photon wave functions, respectively. Lieb and Loss showed that c alpha ^{1/2} Lambda ^{3/2} le E_{alpha , Lambda } le c^{-1} alpha ^{2/7} Lambda ^{12/7} for some constant c >0. In the present paper, we prove the existence of a constant C < infty , such that |Eα,ΛF1α2/7Λ12/7-1|≤Cα4/105Λ-4/105\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\begin{aligned} \\bigg | \\frac{E_{\\alpha , \\Lambda }}{F_1 \\, \\alpha ^{2/7} \\, \\Lambda ^{12/7}} - 1 \\bigg | \\ \\le \\ C \\, \\alpha ^{4/105} \\, \\Lambda ^{-4/105} \\end{aligned}$$\\end{document}holds true, where F_1 >0 is an explicit universal number. This result shows that Lieb and Loss’ upper bound is actually sharp and gives the asymptotics of E_{alpha , Lambda } uniformly in the limit alpha rightarrow 0 and in the ultraviolet limit Lambda rightarrow infty .

One-loop contributions to the decay H → νl̅νlγ in the Standard Model revisited

Abstract One-loop contributions to the decay H → νl̅νlγ with l = e, μ, τ within the Standard Model framework are revisited in this paper. We derive two representations for the form factors in this calculation. As a result, the computations are not only checked numerically by verifying the ultraviolet finiteness of the results but also confirming the ward identity of the amplitude. We find that the results have good stability with varying ultraviolet cutoff parameters as well as satisfying the ward identity. In phenomenological results, we study the partial decay widths for the decay channels in the two cases of the detected photon and invisible photon. Differential decay widths are also generated as a function of the energy of the final photon.

Unitarity problems for an effective field theory description of early universe cosmology

In the context of Effective Field Theory, the Hilbert space of states increases in an expanding universe. Hence, the time evolution cannot be unitary. The formation of structure is usually studied using effective field theory techniques. We study the constraints on effective field theory analyses of early universe models which come from demanding that the factor of the space of states corresponding to length scales where the primordial fluctuations are manifest does not suffer from the unitarity problem. For bouncing and emergent cosmologies, no constraints arise provided that the energy scale of the bounce or emergent phases is smaller than the ultraviolet (UV) cutoff scale. On the other hand, in the case of the inflationary scenario, non-trivial upper bounds on the energy scale of inflation arise.

Mg(H2O)6[(IO2(OH))2(IO3)]2: a new iodate with a very large band gap and optical anisotropy

Centimeter-sized crystals of an iodate with a very large ultraviolet cutoff edge and optical anisotropy were discovered.

Sc2F2(B2O5): a deep ultraviolet scandium borate fluoride exhibiting large birefringence induced by the synergistic effect of B2O5and ScOnF2groups

A rare earth borate fluoride, Sc2F2(B2O5), displays a deep ultraviolet cutoff edge (&lt;200 nm) and very large birefringence induced by the synergistic effect of B2O5and ScOnF2groups.

Na3YB8O15: a new rare-earth borate with an infinite one-dimensional [B8O15]∞ chain and a short ultraviolet cutoff edge.

A new rare-earth borate Na3YB8O15 was fabricated by the flux method. The compound crystallizes in the P1̄ group, and shows a three-dimensional network built by [B8O17] fundamental building blocks (FBBs) with [NaO6], [NaO7], and [YO7] polyhedra. The [B8O17] FBBs are composed of five planar BO3 and three BO4 tetrahedra and connected via corner-sharing to construct a unique one-dimensional (1D) [B8O15]∞ infinity chain that is observed for the first time in the Na2O-Y2O3-B2O3 system compound, enriching the structural diversity of rare-earth borate. The title compound exhibits a short ultraviolet (UV) cutoff edge of ∼195 nm and a wide experimental band gap of 5.50 eV. DFT calculations indicate that Na3YB8O15 is a direct band gap compound with a calculated GGA band gap of 5.14 eV, and the band gap is mainly determined by B 2p and O 2p orbitals. The results update the phase diagram of Na2O-Y2O3-B2O3 and enrich the diversity of rare-earth metal borates.

Extra-dimensional model of dark matter

We present a model for dark matter with extra spatial dimensions in which Standard-Model (SM) fermions have localized wave functions. The underlying gauge group is $G_{\rm SM} \otimes {\rm U}(1)_z$, and the dark matter particle is a SM-singlet Dirac fermion, $\chi$, which is charged under the ${\rm U}(1)_z$ gauge symmetry. We show that the conventional wisdom that the mass of a Dirac fermion is naturally at the ultraviolet cutoff scale does not hold in this model. We further demonstrate that this model yields a dark matter relic abundance in agreement with observation and discuss constraints from direct and indirect searches for dark matter. The dark matter particle interacts weakly with matter and has negligibly small self-interactions. Very good fits to data from cosmological observations and experimental dark matter searches are obtained with $m_\chi$ in the multi-TeV range. A discussion is given of observational signatures and experimental tests of the model.

Quantum generalized hydrodynamics of the Tonks–Girardeau gas: density fluctuations and entanglement entropy

We apply the theory of quantum generalized hydrodynamics (QGHD) introduced in (2020 Phys. Rev. Lett. 124 140603) to derive asymptotically exact results for the density fluctuations and the entanglement entropy of a one-dimensional trapped Bose gas in the Tonks–Girardeau (TG) or hard-core limit, after a trap quench from a double well to a single well. On the analytical side, the quadratic nature of the theory of QGHD is complemented with the emerging conformal invariance at the TG point to fix the universal part of those quantities. Moreover, the well-known mapping of hard-core bosons to free fermions, allows to use a generalized form of the Fisher–Hartwig conjecture to fix the non-trivial spacetime dependence of the ultraviolet cutoff in the entanglement entropy. The free nature of the TG gas also allows for more accurate results on the numerical side, where a higher number of particles as compared to the interacting case can be simulated. The agreement between analytical and numerical predictions is extremely good. For the density fluctuations, however, one has to average out large Friedel oscillations present in the numerics to recover such agreement.

Ba2B13O19(OH)5·5H2O: A promising nonlinear optical material with a unique 2[B13O19(OH)5]∞ two-dimensional layer

A case of hydrous borate with the formula of Ba2B13O19(OH)5·5H2O was synthesized by the traditional hydrothermal method. It crystallizes in the chiral P1 space group and has a unique two-dimensional 2[B13O19(OH)5]∞ layer that is constructed by the hydrogen involved [B13O22(OH)5] fundamental building blocks (FBBs). The Ba atoms and H2O molecules are filled in the three-dimensional pore constructed by the 2[B13O19(OH)5]∞ layer. Interestingly, Ba2B13O19(OH)5·5H2O is the first case of hydrous borates that has the above rare [B13O22(OH)5] FBB and 2[B13O19(OH)5]∞ layer, which enriching the structural chemistry of borate system. The diffuse reflection spectrum result shows that the ultraviolet (UV) cutoff edge of Ba2B13O19(OH)5·5H2O is below 200 nm. Its second harmonic generation (SHG) response is approximately 1.0 times that of potassium dihydrogen phosphate at the 1064 nm fundamental wavelength and it is also phase-matchable. Both results indicate that the title compound is a nonlinear optical crystal for UV spectral region. Theoretical simulation calculation shows that the occupied VE states are mainly contributed by the O-2p orbitals, and therefore [B13O22(OH)5] groups are the main sources of SHG effects.

From β‐Na2B6O10 to Na3AlB8O15 and Na3Al2B7O15: Structural Tuning of Anionic‐Group Architectures by Substitution of [BO4] by [AlO4] Covalent Tetrahedra

Two new sodium aluminum borates, Na3 AlB8 O15 and Na3 Al2 B7 O15 , have been successfully synthesized by the high-temperature solution method. They crystallize in the different space groups, P21 /c and P2/c, respectively. The B-O configurations of β-Na2 B6 O10 , Na3 AlB8 O15 and Na3 Al2 B7 O15 are compared to feature complicated different dimensional open-framework structures caused by the substitution of [BO4 ] by [AlO4 ] covalent tetrahedra. Moreover, the experimental results indicate that Na3 AlB8 O15 and Na3 Al2 B7 O15 have short ultraviolet (UV) cutoff edges (<187 nm). The first-principles calculations show that Na3 AlB8 O15 and Na3 Al2 B7 O15 have moderate birefringence (0.075 and 0.041@1064 nm, respectively).