Spin Lifetime and Charge Noise in Hot Silicon Quantum Dot Qubits

Area of Science:

• Quantum Computing
• Condensed Matter Physics
• Materials Science

Background:

• Silicon quantum dots are promising platforms for scalable quantum computing.
• Understanding and controlling electron spin dynamics is critical for qubit coherence.

Purpose of the Study:

• To investigate the magnetic field and temperature dependence of single-electron spin lifetime in silicon quantum dots.
• To develop a theoretical model explaining spin relaxation mechanisms.
• To assess the impact of temperature on charge noise.

Main Methods:

• Experimental measurements of spin lifetime under varying magnetic fields and temperatures.
• Development of a theoretical model incorporating spin-valley mixing.
• Analysis of temperature-dependent charge noise.

Main Results:

• A spin lifetime of 2.8 ms was achieved at 1.1 K.
• Johnson noise limits relaxation at low temperatures, while two-phonon processes dominate at high temperatures.
• Charge noise exhibits a linear dependence on temperature up to 4 K.

Conclusions:

• The study provides a comprehensive understanding of spin relaxation mechanisms in silicon quantum dots.
• The findings suggest potential for improved qubit operation at higher temperatures.
• This research contributes to the advancement of silicon-based quantum information processing.