Spin Qubit in a 2D Gd^IIINa^I‐Based Oxamato Supramolecular Coordination Framework

Abstract

Qubits are the basic unit of quantum information and computation. To realize quantum computing and information processing, the decoherence times of qubits must be long enough. Among the studies of molecule‐based electron spin qubits, most of the work focused on the ions with the spin S=1/2, where only single‐bit gates can be constructed. However, quantum operations require the qubits to interact with each other, so people gradually carry out relevant research in ions or systems with S>1/2 and multilevel states. In this work, a two‐dimensional (2D) oxygen‐coordinated GdIIINaI‐based oxamato supramolecular coordination framework, Na[Gd(4‐HOpa)4(H2O)] ⋅ 2H2O (1, 4‐HOpa=N‐4‐hydroxyphenyloxamate), was selected as a possible carrier of qubit. The field‐induced slow magnetic relaxation shows this system has phonon bottleneck (PB) effect at low temperatures with a very weak magnetic anisotropy. The pulse electron paramagnetic resonance studies show the spin‐lattice and spin‐spin relaxation times are T1=1.66 ms at 4 K and Tm=4.25 μs at 8 K for its diamagnetically diluted sample (1Gd0.12 %). It suggested that the relatively long decoherence time is mainly ascribed to its near isotropic and the PB effect from resonance phonon trapped for pure sample, while the dilution further improves its qubit performance.

Calculation of π Using a Molecular Electron Spin Qubit Implemented by Pulsed Electron Paramagnetic Resonance

“…The use of molecular electron spins as qubits is also attracting the attention of researchers. − To control such qubits, it is proposed to use pulsed electron paramagnetic resonance (EPR). − Nowadays, there are even opportunities to address the spin center and, thus, perform operations with more than one qubit. − Approaches to characterize a molecular electron spin qubit include relevant EPR spectroscopy techniques. To estimate the coherence time of the qubit, time of transverse relaxation of magnetization ( T 2 ) or phase memory time ( T m ) could be measured .…”