From megahertz to terahertz qubits encoded in molecular ions: theoretical analysis of dipole-forbidden spectroscopic transitions in N₂⁺

Abstract

Theoretical study of the implementation of qubits and clock transitions in the spin, rotational, and vibrational degrees of freedom of molecular nitrogen ions including the effect of magnetic fields.

Non-destructive State Detection and Spectroscopy of Single Molecules

“…[36] However, due to higher order terms in the multipole expansion of the interaction of matter with radiation, weak electric-quadrupole, magnetic-dipole and higher-order rovibrational transitions are allowed. [36][37][38] Such weak transitions exhibit extremely narrow natural linewidths and consequently very long state lifetimes. These properties render N + 2 an ideal test-bed for precision spectroscopic studies, [37,38] for chemical reactions and collision studies in specific internal states, [16,[39][40][41] for the realization of mid-IR frequency standards and molecular clocks, [37,42] for tests of possible temporal variations in the electron-to-proton mass ratio [43] and for the implementation of molecular qubits used in quantum information and computation applications.…”

“…These properties render N + 2 an ideal test-bed for precision spectroscopic studies, [37,38] for chemical reactions and collision studies in specific internal states, [16,[39][40][41] for the realization of mid-IR frequency standards and molecular clocks, [37,42] for tests of possible temporal variations in the electron-to-proton mass ratio [43] and for the implementation of molecular qubits used in quantum information and computation applications. [37]…”

“…This increased sensitivity of measurements and high degree of control are a prerequisite for the application of single molecules as frequency standards and as quantum bits. [37] It also opens perspectives for studies of collisions and chemical reaction between ions and neutrals with precise state control on the single molecule level.…”

SI-traceable frequency dissemination at 1572.06 nm in a stabilized fiber network with ring topology

“…Here we demonstrated the im-provement of the frequency reference in a remote laboratory by two orders of magnitude compared to the previously employed GPSD Rubidium clock standard. As prospective applications of the present frequency-transfer network, we envisage precision spectroscopy of molecular ions [25,36] and of Rydberg atoms and molecules . Rate of corrected errors between two transponders in 3 selected data channels (CH17, CH27.5 and CH50.5) sharing fibers with the metrological signal.…”

Electric-field dissociation of weakly bound molecular ions

“…The advent of hybrid neutral-ion traps has boosted cold chemistry research due to the possibility of bringing together ions and atoms in a controlled manner [1][2][3][4][5]. Similarly, these traps find applications in different research areas such as the development of new and more efficient quantum information protocols [6][7][8][9][10][11][12][13], the realization of quantum logic spectroscopy schemes [14][15][16][17][18][19][20] and the study of impurity physics [21][22][23][24][25][26][27][28][29], to cite a few. On the impurity physics front, when a single charged impurity, A + , is brought in contact with an ultracold atomic gas B, at sufficient densities, the ion undergoes a three-body recombination reaction: A + + B + B→ AB + + B leading to the formation of weakly bound molecular ions [1,30,31].…”