Quantum computing with collective ensembles of multilevel systems.

Area of Science:

• Quantum Computing
• Atomic Physics
• Quantum Information Science

Background:

• Current quantum computing architectures face challenges in scalability and stability.
• Encoding quantum information in individual quantum systems can be prone to decoherence.

Purpose of the Study:

• To propose a new physical approach for encoding and processing quantum information.
• To demonstrate the feasibility of building scalable quantum computers using collective quantum states.

Main Methods:

• Utilizing ensembles of multilevel quantum systems.
• Implementing one- and two-bit gates via collective internal state transitions.
• Employing an excitation blockade mechanism to restrict state populations to zero or unity.

Main Results:

• The proposed scheme allows quantum information to be encoded in the collective population of internal atomic levels.
• Excitation blockade ensures that each internal state is populated by at most one excitation, simplifying control.
• Quantum computers with 10-20 bits are achievable in single trapped atomic clouds.

Conclusions:

• The developed physical approach offers a promising route for building robust and scalable quantum computers.
• The linear relationship between register size and the number of internal quantum states provides a pathway to larger quantum registers.
• This method leverages the Rydberg excitation blockade mechanism in trapped atoms for quantum information processing.