Ultralong Spin-Coherence Times for Rubidium Atoms in Solid Parahydrogen via Dynamical Decoupling

Abstract

Coherence time is an essential parameter for quantum sensing, quantum information, and quantum computation. In this work, we demonstrate electron spin coherence times as long as 0.1 s for an ensemble of rubidium atoms trapped in a solid parahydrogen matrix. We explore the underlying physics limiting the coherence time. The properties of these matrix isolated atoms are very promising for future applications, including quantum sensing of nuclear spins. If combined with efficient singleatom readout, this would enable NMR and MRI of single molecules co-trapped with alkali-metal atom quantum sensors within a parahydrogen matrix.

Long-lived quantum coherent dynamics of a $Λ$-system driven by a thermal environment

“…The lifetime of quantum superposition states is limited by their interaction with an external environment [4][5][6], whose fluctuations affect the relative phases between the different components of the superposition, leading to the production of high-entropy mixed states (such as thermal states), which are much less useful for quantum information processing than their low-entropy counterparts [5]. Identifying and suppressing decoherence in atomic and molecular systems interacting with external environments is therefore a central goal of quantum information science, which motivated the development of decoupling techniques for solid-state qubits [3,[7][8][9][10][11], engineering decoherencefree subspaces [12,13], and the search for decoherenceminimizing clock transitions and magic trapping conditions for atomic [14,15] and molecular [16] qubits.…”

High-purity solid parahydrogen

“…Recent experiments have shown that atoms trapped in solid hydrogen also retain their key properties for use as quantum sensors for magnetic fields: it is possible to control and measure the spin states of the implanted atoms through optical techniques 3,4 , and the trapped atoms exhibit both long ensemble spin dephasing times (T * 2 ) 4,5 and long spin coherence times (T 2 ) 6 . However, the coherence time T 2 of the electron spin states of the implanted atoms was found to be limited by orthohydrogen impurities in the solid 6 . In separate experiments, NMR measurements of HD molecules in solid parahydrogen showed that the ensemble nuclear spin dephasing time T * 2 of the HD molecules was also limited by orthohydrogen 7,8 .…”

“…Prior work has explored the use of a variety of catalysts and methods of sample growth [14][15][16][17][18][19][20] . The lowest orthohydrogen fractions are likely obtained by implanting high densities of catalyst atoms or molecules directly into solid parahydrogen, where they can serve to achieve para-ortho thermal equilibrium at arbitrarily low temperatures 6,21 . However, because the catalyst itself has undesirable magnetic properties, in our work the parahydrogen must be extracted from the catalyst for deposition elsewhere.…”

High Resolution Spectroscopy of Neutral Yb Atoms in a Solid Ne Matrix

“…Spin coherence times of the guest species, which are ultimately dominated by long-range dipolar couplings [1,2], could be made as long as 10 3 s for nuclear spins and 1 s for electronic spins by minimizing spin impurities within the host matrix. Applications of this "matrix isolation" technique include tests of fundamental symmetries [3,4], magnetometry [5,6] and quantum information science [7].…”

“…Despite substantial matrix-induced perturbations to their D-lines, however, alkali atoms have been successfully optically pumped in matrix isolation [5,13]. Furthermore, spin coherence times as long as 0.1 s have been observed for Rb atoms in solid parahydrogen [6].…”