Constraints on the spatial variation of Planck constant

Inspired by recently published researches, we present two protocols for setting an upper limit to the claimed variation of $$\hbar $$ ħ upon the position. The protocols, both within today state of art, involve the use of two delayed laser pulses driving an atom. The distinct positions of the laboratory, due to the Earth motion, affects $$\hbar $$ ħ and hence the atomic dynamics. The first protocol measures the difference in population of the atomic ground state while the second one the red-shift of the harmonics emitted by the atom in the two moments of the experiment. The protocols improve the reported upper limit of $$\varDelta \hbar /\hbar $$ Δ ħ / ħ . The theory shows that $$\hbar (\varvec{r})$$ ħ ( r ) induces a chaotic evolution to the atom. This form of Chaos is generated by a variation of a physical parameter and is one example of Parametric Chaos.

Towards a compact, optically interrogated, cold-atom microwave clock

A compact platform for cold atoms opens a range of exciting possibilities for portable, robust and accessible quantum sensors. In this work, we report on the development of a cold-atom microwave clock in a small package. Our work utilises the grating magneto-optical trap and high-contrast coherent population trapping in the lin$\perp $lin polarisation scheme. We optically probe the atomic ground-state splitting of cold 87Rb atoms using a Ramsey-like sequence whilst the atoms are in free-fall. We have measured a short-term fractional frequency stability of $5{\times}{10}^{-11}/\sqrt{\tau }$ with a projected quantum projection noise limit at the ${10}^{-13}/\sqrt{\tau }$ level.

P , T -Violating and Magnetic Hyperfine Interactions in Atomic Thallium

We present state-of-the-art string-based relativistic general-excitation-rank configuration interaction and coupled cluster calculations of the electron electric dipole moment, the nucleon–electron scalar-pseudoscalar, and the magnetic hyperfine interaction constants ( α d e , α C S , A | | , respectively) for the thallium atomic ground state 2 P 1 / 2 . Our present best values are α d e = − 558 ± 28 , α C S = 6.77 ± 0.34 [ 10 − 18 e cm], and A | | = 21172 ± 1059 [MHz]. The central value of the latter constant agrees with the experimental result to within 0.7% and serves as a measurable probe of the P , T -violating interaction constants. Our findings lead to a significant reduction of the theoretical uncertainties for P , T -odd interaction constants for atomic thallium but not to stronger constraints on the electron electric dipole moment, d e , or the nucleon–electron scalar-pseudoscalar coupling constant, C S .

Ionization Cross Sections by Electron Impact for Single Ionization from the Atomic Ground State

Using the empirical formula with three free parameters recently proposed, ionization cross sections are given for the representation of cross sections for single ionization of free atoms from the ground stages by electron impact. Almost all experimental results can be approximated by this formula with 20% over the whole energy range between the threshold and 1 . All experimental results can be approximated with experimental error. The formula proposed is not suitable to regenerate the exact contour of fine structure in the ionization cross section curve. The probable error is estimated to be approximately 20%, but the error is larger than 40% and no fine structures are accounted for near the threshold.

New analytical independent-particle model potential for atoms

A new analytical, independent-particle model potential with four shell-independent parameters is proposed, which is suitable for high, medium, and low Z atoms. The four parameters are determined for 101 atoms from Li to Lr by fitting the results of the X a method found in the literature. The average fitting error 0.675% of the new potential for the 101 atoms is far better than 3.92% of the widely used Green’s potential. The radial Schrödinger equation with the new potential is solved by using Numerov’s numerical method for 7 typical atoms: Ne, Ca, Zn, Zr, Sn, Yb, and Th. The energy eigenvalues, radial wave functions, and atomic ground-state energy are in good agreement with the results of the X a method. The new potential here shows greater flexibility and better accuracy compared with the Green’s potential.