Semi-empirical Haken–Strobl model for molecular spin qubits
Abstract
Understanding the physical processes that determine the relaxation T 1 and dephasing T 2 times of molecular spin qubits is critical for envisioned applications in quantum metrology and information processing. Recent spin-echo measurements of solid-state molecular spin qubits have stimulated the development of quantum mechanical models for predicting intrinsic qubit timescales using first-principles electronic structure methods. We develop an alternative semi-empirical approach to construct Redfield quantum master equations for molecular spin qubits using a stochastic Haken–Strobl theory for a central spin with fluctuating gyromagnetic tensor due to spin-lattice interaction and fluctuating local magnetic field due to interactions with lattice spins. Using two vanadium-based spin qubits as case studies, we compute qubit population and decoherence times as a function of temperature and magnetic field, using a bath spectral density parametrized with a small number of T 1 measurements. The theory quantitatively agrees with experimental data over a range of conditions beyond those used to parameterize the model, demonstrating the generalization potential of the method. The ability of the model to describe the temperature dependence of the ratio T 2 / T 1 is discussed and possible applications for designing novel molecule-based quantum magnetometers are suggested.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 01, 2023
- Source ID
- 10.1088/1367-2630/acf2bd
Entities
People
- Daniel Aravena
- Felipe Herrera
- Katy Aruachan
- Yamil J Colón
Organizations
- Air Force Office of Scientific Research
- Chilean National Agency for Research and Development
- National Fund for Scientific and Technological Development