Toward a New Generation of Compact Transportable Yb+ Optical Clocks

Abstract

Optical atomic clocks are currently one of the most sensitive tools making it possible to precisely test the fundamental symmetry properties of spacetime and Einstein’s theory of relativity. At the same time, the extremely high stability and accuracy of compact transportable optical clocks open new perspectives in important fields, such as satellite navigation, relativistic geodesy, and the global time and frequency network. Our project aimed to develop a compact transportable optical clock based on a single ytterbium ion. We present the first prototype of the Yb+ clock (298 kg in 1 m3) and present several solutions aimed to improve the clock’s robustness to approach the demands of a space-qualified system. We present spectroscopic studies of a 435.5 nm quadrupole clock transition with Fourier-limited spectra of 25 Hz. The estimated instability of the output frequency at 1 GHz, which was down-converted with an optical frequency comb (OFC), is at the level of 9×10−15/τ, and the long-term instability and inaccuracy are at the level of 5×10−16. As the next steps, we present a new design for the clock laser and the OFC.

Proposal for Trapped-Ion Quantum Memristor

“…Other possible candidates for the quantum memristor realization could be NV centers or other synthesized atoms with specific energy level state properties (selected three levels with corresponding lifetimes). At the same time, an advantage of the ion-based memristive concept is the fact that it can be realized as a standard for ion-base quantum computing and optical atomic clock techniques [ 26 , 27 ].…”

“…Furthermore, an ion-based memristor benefits from straightforward possibility to use common vibrational modes in the trap for ion–ion entanglement. An additional advantage of the ion-based memristive concept is the fact that it can be realized as a standard for ion-based quantum computing and optical atomic clock techniques [ 26 , 27 ].…”

Methods of quantum logic in ion frequency standards, quantum computers, and modern spectroscopy

“…The unique properties of single ions captured in a Paul trap, such as (1) the wide variety of research subjects (virtually any ion can be trapped), (2) the presence of spectrally narrow `clock' transitions that are weakly sensitive to constant electric fields and blackbody radiation, (3) the absence of the contribution of the first-order Doppler effect, and (4) the absence of external perturbing fields in the trap (the ion is at zero quadrupole potential; there is no magnetic field), make them one of the best frequency references. Other advantages are the compactness of the trap, the simplicity of the loading system, a deep confining potential, and a long ion lifetime, amounting to weeks and months, depending on the vacuum level [41]. Probably, the only drawback is the relatively scant statistics on counts in the fluorescence signal of a single ion (compared to optical clocks based on ensembles of neutral atoms) and, accordingly, a decrease in the stability of the system frequency at intervals of 1±100 s by about an order of magnitude compared to clocks based on optical lattices, where 10 4 À10 5 atoms are interrogated simultaneously.…”

“…One of the important areas in the development of optical frequency standards, which, in fact, has become technological, is the reduction in their size and the transition to transportable systems and, in the future, to space-based systems. A number of projects are underway to develop transportable clocks based on Yb [41,62], Ca [63] and Al [64] single ions. Since 2018, a transportable standard based on a single ytterbium ion has been under development at LPI [41].…”

“…A number of projects are underway to develop transportable clocks based on Yb [41,62], Ca [63] and Al [64] single ions. Since 2018, a transportable standard based on a single ytterbium ion has been under development at LPI [41]. It was shown that the developed setup with dimensions of 1 m 3 and a weight of 300 kg provided instability of frequency reproduction of better than 5 Â 10 À16 with transfer to the radio frequency range (1 GHz) using a femtosecond optical frequency synthesizer (FOFS).…”