Quantum interface of an electron and a nuclear ensemble.

Area of Science:

• Quantum Information Science
• Solid-State Physics
• Quantum Many-Body Systems

Background:

• Quantum many-body phenomena rely on coherent excitation of quantum objects.
• Quantum memories are crucial for storing quantum information.
• A deterministic, coherent interface between spin qubits and ensembles is currently lacking.

Purpose of the Study:

• To establish a deterministic and coherent interface between a spin qubit and a nuclear spin ensemble.
• To engineer a local quantum memory for individual quantum-dot spin qubits.
• To advance solid-state platforms for quantum-state engineering of many-body systems.

Main Methods:

• Electron cooling of a mesoscopic nuclear spin ensemble in a semiconductor quantum dot to the nuclear sideband-resolved regime.
• Implementation of an all-optical approach for accessing quantized electronic-nuclear spin transitions.
• Performing coherent optical rotations on a single collective nuclear spin excitation (spin wave).

Main Results:

• Achieved cooling of nuclear spin ensembles to the nuclear sideband-resolved regime.
• Demonstrated all-optical access to individual quantized electronic-nuclear spin transitions.
• Successfully performed coherent optical rotations of a single collective nuclear spin excitation.

Conclusions:

• The study provides essential building blocks for a local quantum memory associated with each quantum-dot spin qubit.
• The developed techniques pave the way for a solid-state platform for quantum-state engineering of isolated many-body systems.
• This work addresses the long-standing challenge of creating a coherent interface for quantum information storage.