On ergodic and mixing properties of the triangle map

In this paper, we study in detail, both analytically and numerically, the dynamical properties of the triangle map, a piecewise parabolic automorphism of the two-dimensional torus, for different values of the two independent parameters defining the map. The dynamics is studied numerically by means of two different symbolic encoding schemes, both relying on the fact that it maps polygons to polygons: in the first scheme we consider dynamically generated partitions made out of suitable sets of disjoint polygons, in the second we consider the standard binary partition of the torus induced by the discontinuity set. These encoding schemes are studied in detail and shown to be compatible, although not equivalent. The ergodic properties of the triangle map are then investigated in terms of the Markov transition matrices associated to the above schemes and furthermore compared to the spectral properties of the Koopman operator in L²(T²). Finally, a stochastic version of the triangle map is introduced and studied. A simple heuristic analysis of the latter yields the correct statistical and scaling behaviours of the correlation functions of the original map.     

Proton-neutron and proton-proton correlations in medium-weight nuclei and the role of the tensor force

A detailed analysis of the effect of short-range and tensor correlations on one- and two-nucleon momentum distributions of medium-weight nuclei (12相似文献   

Thermodynamical Limit for Correlated Gaussian Random Energy Models

 Let {E _Σ (N)} _ΣΣN be a family of |Σ _N |=2 ^N centered unit Gaussian random variables defined by the covariance matrix C _N of elements c _N (Σ,τ):=Av(E _Σ (N)E _τ (N)) and the corresponding random Hamiltonian. Then the quenched thermodynamical limit exists if, for every decomposition N=N ₁ +N ₂ , and all pairs (Σ,τ)Σ _N ×Σ _N :

Subsidiary conditions and variational calculations of nuclear and neutron matters

The energy of nuclear and neutron matter is calculated within the framework of the variational approach including the contribution from three-body clusters. Two types of constrains for the two-body correlation function and realistic S-wave forces are used. It is shown that the energy strongly depends upon the type of constraint and that the variational calculation may lead to much more energy than the lowest order Brueckner theory calculations.     

Equilibrium structure and force field of nitrosyl chloride

The a-type rotational spectra of ¹⁶O¹⁵N³⁵Cl in the (100) excited vibrational state ($\text{ν}{}_1\text{? 1770}\text{cm}{}^{\mathrm{?1}}$) and of ¹⁸O¹⁵N³⁵Cl and ¹⁸O¹⁴N³⁷Cl in the ground state were observed. The equilibrium structure of nitrosyl chloride was calculated from the values of the equilibrium rotational constants B_e and C_e of the two isotopic species ¹⁶O¹⁴N³⁵Cl and ¹⁶O¹⁵N³⁵Cl. The ground-state rotational constants of seven isotopic species of nitrosyl chloride were used to calculate Watson's r_m structure, which was found to be in satisfactory agreement with the r_e structure. The quadratic and cubic force fields of nitrosyl chloride were simultaneously refined by optimizing the least-squares fit to a set of 48 experimental data which includes the sextic centrifugal distortion constants, with one quadratic and three cubic terms of the potential energy function constrained to the values computed by SCF/ab initio methods. All remaining quadratic and cubic SCF force constants were found to be in reasonably close agreement with the empirically determined constants.     

Centrifugal distortion and the ring puckering vibration in the microwave spectrum of 2,3-dihydrofuran

The microwave spectrum of 2,3-dihydrofuran has been reinvestigated and measurements for the ground and first five excited states of the ring puckering vibration have been extended to higher frequencies and rotational quantum numbers in order to study the vibrational dependence of the rotational and centrifugal distortion constants. The ring puckering potential function derived by Green from the far infrared spectrum does not reproduce the vibrational dependence of the rotational constants well. A slightly different potential function is derived which gives a reasonable fit both to the far infrared spectrum and the rotational constants. This changes the barrier to ring inversion from 1.00 kJ mol⁻¹ to 1.12 kJ mol⁻¹. The vibrational dependence of the centrifugal distortion constants is accounted for satisfactorily by the theory developed by Creswell and Mills. An attempt to reproduce the vibrational dependence of the rotational and centrifugal distortion constants using the ring puckering potential function and a simple model for this vibration has very limited success.     

Qubit teleportation and transfer across antiferromagnetic spin chains

We explore the capability of spin-1/2 chains to act as quantum channels for both teleportation and transfer of qubits. Exploiting the emergence of long-distance entanglement in low-dimensional systems [Phys. Rev. Lett. 96, 247206 (2006)10.1103/Phys.Rev.Lett.96, 247206(2006)], here we show how to obtain high communication fidelities between distant parties. An investigation of protocols of teleportation and state transfer is presented, in the realistic situation where temperature is included. Basing our setup on antiferromagnetic rotationally invariant systems, both protocols are represented by pure depolarizing channels. We propose a scheme where channel fidelity close to 1 can be achieved on very long chains at moderately small temperature.     

1,10-Phenanthrolines with tunable luminescence upon protonation: a spectroscopic and computational study

We have synthesized nine 2,9-aryl-substituted 1,10-phenanthrolines (1-9) with the aim of rationalizing their electronic absorption and luminescence properties in both the basic and acid form. The latter are generated upon addition of trifluoroacetic acid to CH2Cl2 solutions of 1-9 and their formation is unambiguously evidenced by UV-vis absorption and 1H NMR spectroscopy. 1-9 can be subdivided into three groups, depending on their chemical structure and luminescence behavior. 1-3 are symmetrically substituted p-dianisylphenanthrolines which exhibit relatively intense violet fluorescence in CH2Cl2 (lambda(max) ca. 400 nm, Phi(fl) = 0.12-0.33) and are strongly quenched and substantially red-shifted upon protonation (lambda(max) ca. 550 nm, Phi(fl) = 0.010-0.045). 4-5 are 2,6-dimethoxyphenylphenanthrolines with faint luminescence in both the basic and acid form. 6-9 are various unsymmetric aryl-substituted-phenanthrolines and their relatively strong fluorescence (lambda(max) ca. 400 nm, Phi(fl) = 0.08-0.24) is red-shifted and substantially enhanced following protonation (lambda(max) ca. 475 nm, Phi(fl) = 0.16-0.50). The markedly different trends in the electronic absorption and fluorescence spectra are rationalized by means of both time-dependent Hartree-Fock and density functional theory by using hybrid functionals to assign the excited states. Interestingly, protonation of 1-9 also occurs in spin-coated films simply exposed to vapors of acid, and the reaction can be signaled by the color tuning of the emission signal (vapoluminescence). This observation makes substituted phenanthrolines potential candidates as proton sensors also in the solid phase.     

Turning on red and near-infrared phosphorescence in octahedral complexes with metalated quinones

We report the synthesis of π-bonded ruthenium, rhodium, and iridium o-benzoquinones [Cp*M(o-C(6)H(4)O(2))](n) [M = Ru (2), n = 1-; Rh (3), n = 0; Ir (4), n = 0] following a novel synthetic procedure. Compounds 2-4 were fully characterized by spectroscopic methods and used as chelating organometallic linkers, "OM-linkers", toward luminophore bricks such as Ru(bpy)(2)(2+), Rh(ppy)(2)(+), and Ir(ppy)(2)(+) (bpy = 2,2'-bipyridine; ppy = 2-phenylpyridine) for the design of a novel family of octahedral bimetallic complexes of the general formula [(L-L)(2)M(OM-linkers)][X](m) (X = counteranion; m = 0, 1, 2) whose luminescent properties depend on the choice of the OM-linker and the luminophore brick. Thus, dinuclear assemblies such as [(bpy)(2)Ru(2)][OTf] (5-OTf), [(bpy)(2)Ru(2)][Δ-TRISPHAT] (5-ΔT) {TRISPHAT = tris[tetrachlorobenzene-1,2-bis(olato)]phosphate}, [(bpy)(2)Ru(3)][OTf](2) (6-OTf), [(bpy)(2)Ru(4)][OTf](2) (7-OTf), [(bpy)(2)Ru(4)][Δ-TRISPHAT](2) (7-ΔT), [(ppy)(2)Rh(2)] (8), [(ppy)(2)Rh(3)][OTf] (9-OTf), [(ppy)(2)Rh(4)][OTf] (10-OTf), [(ppy)(2)Rh(4)][Δ-TRISPHAT] (10-ΔT), [(ppy)(2)Ir(2)] (11), [(ppy)(2)Ir(3)][OTf] (12-OTf), [(ppy)(2)Ir(4)][OTf] (13-OTf), and [(ppy)(2)Ir(4)][Δ-TRISPHAT] (13-ΔT) were prepared and fully characterized. The X-ray molecular structures of three of them, i.e., 5-OTf, 8, and 11, were determined. The structures displayed a main feature: for instance, the two oxygen centers of the OM-linker [Cp*Ru(o-C(6)H(4)O(2))](-) (2) chelate the octahedral chromophore metal center, whether it be ruthenium, rhodium, or iridium. Further, the carbocycle of the OM-linker 2 adopts a η(4)-quinone form but with some catecholate contribution due to metal coordination. All of these binuclear assemblies showed a wide absorption window that tailed into the near-IR (NIR) region, in particular in the case of the binuclear ruthenium complex 5-OTf with the anionic OM-linker 2. The latter feature is no doubt related to the effect of the OM-linker, which lights up the luminescence in these homo- and heterobinuclear compounds, while no effect has been observed on the UV-visible and emission properties because of the counteranion, whether it be triflate (OTf) or Δ-TRISPHAT. At low temperature, all of these compounds become luminescent; remarkably, the o-quinonoid linkers [Cp*M(o-C(6)H(4)O(2))](n) (2-4) turn on red and NIR phosphorescence in the binuclear octahedral species 5-7. This trend was even more observable when the ruthenium OM-linker 2 was employed. These assemblies hold promise as NIR luminescent materials, in contrast to those made from organic 1,2-dioxolene ligands that conversely are not emissive.