运动介质的电偶极矩与磁矩

在推导出介质的极化强度与磁化强度的坐标变换公式的基础上,分析导出了运动介质的电偶极矩与磁矩.     

New insights into the neutron electric dipole moment

We analyze the CP-violating electric dipole form factor of the nucleon in the framework of covariant baryon chiral perturbation theory. We give a new upper bound on the vacuum angle, |θ₀|?2.5×¹⁰⁻¹⁰$|{\theta }_0|?2.5\times {10}^{-10}$. The quark mass dependence of the electric dipole moment is discussed and compared to lattice QCD data. We also perform the matching between its representations in the three- and two-flavor theories.     

Quantum holonomies for an electric dipole moment

In this Letter, we obtain the quantum holonomies for a neutral particle with a permanent electric dipole moment based on the analogue effects of the He-McKellar-Wilkens effect and the Scalar Aharonov-Bohm effect and show a new proposal for implementing one-qubit quantum gates.     

Microwave spectrum, molecular structure, dipole moment, and theoretical calculation of cyclopentanone oxime

The microwave spectra of cyclopentanone oxime (C₅H₈NOH) and its deuterated species (C₅H₈NOD) were observed in the frequency region from 9 to 40 GHz. Only a-type R-branch transitions were assigned in the vibrational ground and excited states. The rotational constants of normal species were determined to be A = 5870.80(33), B = 1917.021(8), and C = 1526.784(8) MHz in the vibrational ground state, and A = 5870.16(43), B = 1842.707(9), and C = 1479.401(9) MHz for deuterated species. The dipole moments were determined as μ_a = 0.80(10), μ_b = 0.20(10), and μ_c = 0.40(10) D. The ring-puckering vibrational states were observed up to v = 6. The vibrational mode was nearly harmonic. The fundamental frequency of the ring-puckering mode was found to be 70(20) cm⁻¹. The molecular structure of cyclopentanone oxime was determined to be a twisted configuration by comparing the observed and calculated rotational constants, planar moment of inertia, P_cc, and r_s coordinates of the hydroxyl hydrogen atom. On the molecular geometry, the bond angle, C₂C₁N₆ (Fig. 1), is larger than C₅C₁N₆ by ca. 6°, because of the steric repulsion between the methylene group of C₂ atom and hydroxyl group.     

Analytic solution of the wave equation for an electron in the field of a molecule with an electric dipole moment

We relax the usual diagonal constraint on the matrix representation of the eigenvalue wave equation by allowing it to be tridiagonal. This results in a larger representation space that incorporates an analytic solution for the non-central electric dipole potential cosθ/r², which was believed not to belong to the class of exactly solvable potentials. Therefore, we were able to obtain a closed form solution of the three-dimensional time-independent Schrödinger equation for a charged particle in the field of a point electric dipole that could carry a nonzero net charge. This problem models the interaction of an electron with a molecule (neutral or ionized) that has a permanent electric dipole moment. The solution is written as a series in a basis composed of special functions that support a tridiagonal matrix representation for the angular and radial components of the wave operator. Moreover, this solution is for all energies, the discrete (for bound states) as well as the continuous (for scattering states). The expansion coefficients of the radial and angular components of the wavefunction are written in terms of orthogonal polynomials satisfying three-term recursion relations. For the Coulomb-free case, where the molecule is neutral, we calculate critical values for its dipole moment below which no electron capture is allowed. These critical values are obtained not only for the ground state, where it agrees with already known results, but also for excited states as well.     

Towards a new measurement of the neutron electric dipole moment

Precision measurements of particle electric dipole moments (EDMs) provide extremely sensitive means to search for non-standard mechanisms of T (or CP) violation. For the neutron EDM, the upper limit has been reduced by eight orders of magnitude in 50 years thereby excluding several CP violation scenarios. We report here on a new effort aiming at improving the neutron EDM limit by two orders of magnitude, down to a level of 3 × 10⁻²⁸ e·cm. The two central elements of the approach are the use of the higher densities which will be available at the new dedicated spallation UCN source at the Paul Scherrer Institute, and the optimization of the in-vacuum Ramsey resonance technique, with storage chambers at room temperature, to reach new limits of sensitivity.     

New limit on the permanent electric dipole moment of 199Hg

We present the first results of a new search for a permanent electric dipole moment of the 199Hg atom using a UV laser. Our measurements give d(199Hg) = -(1.06+/-0.49+/-0.40)x10(-28)e cm. We interpret the result as an upper limit absolute value [d(199Hg)]<2.1x10(-28)e cm (95% C.L.), which sets new constraints on theta bar;(QCD), chromo-EDMs of the quarks, and CP violation in supersymmetric models.     

The dipole moment of HOCl in vOH=4

Pulsed laser excitation and photofragment detection methods are used to observe the 17_0,17←16_1,16 pure rotational transition within the v_OH=4 vibrational state of HO³⁵Cl. Microwave frequency and Stark effect measurements give ν₀=27484.33(10) MHz and μ_b=1.562(9) D. The dependence of μ_b, which is approximately parallel to the OH bond, on the level of OH stretch excitation appears linear and is consistent with that of H₂O over the same 0-14 000 cm⁻¹ energy range.     

The effect of a permanent dipole moment on the polar molecule cavity quantum electrodynamics

A dressed-state perturbation theory beyond the rotating wave approximation(RWA) is presented to investigate the interaction between a two-level electronic transition of polar molecules and a quantized cavity field. Analytical expressions can be explicitly derived for both the ground- and excited-state-energy spectrums and wave functions of the system, where the contribution of permanent dipole moments(PDM) and the counter-rotating wave term(CRT) can be shown separately.The validity of these explicit results is discussed by comparison with the direct numerical simulation. Compared to the CRT coupling, PDM results in the coupling of more dressed states and the energy shift is proportional to the square of the normalized permanent dipole difference, and a greater Bloch–Siegert shift can be produced in the giant dipole molecule cavity QED. In addition, our method can also be extended to the solution of the two-level atom Rabi model Hamiltonian beyond the RWA.     

Current rectification in single molecule C59N: Effect of molecular polarity induced dipole moment

By applying non-equilibrium Green's function formalism combined with density functional theory, we have investigated the electronic transport properties of nitrogen doped fullerene absorbed on the self-assembled alkanethiol monolayer. The molecular dipole moment, which in microscopy leads to the molecule-electrode coupling changing asymmetrically is responsible for the observed molecular rectification.     

The electric dipole moment of the muon

The forthcoming experiment [1] on the anomalous magnetic moment of the muon will be able to search also for an electric dipole momentd _μ of the muon with increased sensitivity. A brief survey is given on what various models of CP violation predict ford _μ.     

The electric dipole moment of methyl fluoride

The Stark effect of CH₃F is extensively used as a calibration standard in laser Stark spectroscopy. The accepted value for the dipole moment of the ground vibrational state of CH₃F is less accurate than the precision of laser Stark measurements, and questions have also been raised about the literature value. New molecular beam spectroscopy measurements have been made of the ratio of the Stark effect in the J = 1, K = 1 and J = 2, K = 2 CH₃F states to that of the 01¹0 vibrational state of OCS. The results were $\text{μ}{}_{1.1}\text{(}\text{CH}{}_3\text{F}\text{)}\text{μ}{}_{010}\text{(}\text{OCS}\text{)}\text{= 2.638905(23)}$ and $\text{μ}{}_{2.2}\text{(}\text{CH}{}_3\text{F}\text{)}\text{μ}{}_{010}\text{(}\text{OCS}\text{)}\text{= 2.63894(10)}$. This produces a dipole moment of 1.85840 D with precision relative to OCS of 10 ppm and absolute accuracy of 43 ppm.     

Direct fit of experimental ro-vibrational intensities to the dipole moment function: Application to HCl

A dipole moment function (DMF) for hydrogen chloride (HCl) has been obtained using a direct fit approach that fits the best available and appropriately weighted experimental data for individual ro-vibrational transitions. Combining wavefunctions derived from the Rydberg-Klein-Rees (RKR) numerical method and a semi-empirical DMF, line intensities were calculated numerically for bands with Δv=0, 1, 2, 3, 4, 5, 6, 7 up to v′=7. The results have demonstrated the effectiveness of inclusion of rotational dipole moment matrix elements and appropriate weighting of the experimental data in the DMF fitting. The new method is shown to be superior to the common method of fitting only the rotationless dipole moment elements, while at the same time being simple to implement.     

On the effects on a Landau-type system for an atom with no permanent electric dipole moment due to a Coulomb-type potential

We analyse the bound states for a Landau-type system for an atom with no permanent electric dipole moment subject to a Coulomb-type potential. By comparing the energy levels for bound states of the system with the Landau quantization for an atom with no permanent electric dipole moment (Furtado et al., 2006), we show that the energy levels of the Landau-type system are modified, where the degeneracy of the energy levels is broken. Another quantum effect investigated is a dependence of the angular frequency of the system on the quantum numbers associated with the radial modes and the angular momentum. As examples, we obtain the angular frequency and the energy levels associated with the ground state and the first excited state of the system.     

New all-optical method for measuring molecular permanent dipole moment difference using two-photon absorption spectroscopy

Stark effect, in combination with spectral hole burning and single-molecule spectroscopy, has been a fruitful technique to study permanent electric dipole moment of molecules in condensed phase. However, because measuring Stark shifts relies on external fields and narrow line- or hole-widths, the applicability of this method at ambient conditions required by most biological systems has remained limited. Here we demonstrate a new all-optical method for measuring the molecular dipole moment difference between ground and excited states using two-photon absorption (2PA) spectroscopy. We show that the value and orientation of the static dipole moment difference can be determined from the corresponding absolute 2PA cross-section. We use this new method to determine for the first time the strength of local electric field E_loc=0.1-1.0×10⁸ V/cm inside beta-barrel of Fruit series of red fluorescent proteins. Because our method does not rely on external field and is applicable in liquid solutions, it is well suited for the study of biological systems.     

Nuclear electric dipole moment of He

A permanent electric dipole moment (EDM) of a physical system requires time-reversal (T) and parity (P) violation. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Here we calculate the magnitude of the P-, T-violating EDM of ³He and the expected sensitivity of such a measurement to the underlying P-, T-violating interactions. Assuming that the coupling constants are of comparable magnitude for π-, ρ-, and ω-exchanges, we find that the pion-exchange contribution dominates. Our results suggest that a measurement of the ³He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion–nucleon P-, T-violating interaction.     

Microwave spectrum and dipole moment of pentafluorobenzene

With the idea of evaluating the dipole moment of pentafluorobenzene from a lowJ transition, its microwave spectrum was investigated in the frequency region of 8,000 to 12,400 MHz. The spectrum had been earlier observed by the authors in the 12,400 to 18,000 MHz region which needs reassignment in the light of present investigations. The rotational constants areA=1480·856±0·003 MHz,B=1030·066±0·003 MHz andC=607·496±0·002 MHz. The dipole moment is 1·44±0·05 D.     

铯原子里德堡态Stark能量及电偶极矩的测量和理论计算

里德堡原子由于具有体积大、寿命长、易极化及在外电场中能级易于操控等特点, 已经成为了目前物理学领域研究的热点之一. 本文在磁光阱中实验测量了铯原子15P_3/2和16P_3/2态的Stark光谱,根据光谱给出了15P_3/2和16P_3/2|m|=1/2 Stark态在0-1400 V/cm场强范围适用的Stark 能量和偶极矩的经验性解析表达式; 用数值方法求解薛定谔方程获得了这些态的Stark能量、偶极矩和电子几率密度分布. 电子几率密度分布定性说明了计算的偶极矩矢量的方向是正确的. 计算的Stark能量、偶极矩与实验结果相一致.     

Spectral line parameters in the (2 ← 0) overtone band and the dipole moment function of the HI molecule

We present here new high-resolution experimental data on the linestrengths and pressure-broadened Lorentzian widths for the P₂(13) to R₂(12) vibration-rotation lines in the first overtone absorption band of hydrogen iodide. By combining the measured linestrengths with our previous results for the fundamental band [J. Mol. Spectrosc. 218 (2003) 75] and with other published data for the higher-overtone bands of this molecule, an improved dipole moment expansion as a function of the dimensionless reduced nuclear displacement x is obtained: μ(x)=0.4471(5)−0.0772(2)x+0.542(3)x²−1.90(2)x³. This experimental dipole moment function is compared with the results of a few recent non-relativistic and relativistic ab initio calculations. The agreement between theoretical and experimental Herman-Wallis coefficients for the first two vibrational bands of HI is found best as ever reported before.