Prospects for quantum computing with an array of ultracold polar paramagnetic molecules.

Area of Science:

• Quantum Computing
• Ultracold Molecular Physics
• Quantum Information Science

Background:

• Trapped ultracold molecules are a promising platform for quantum computation.
• Previous work proposed using polar (1)Σ molecules as qubits based on Stark states.
• This research explores a different molecular system for enhanced quantum control.

Purpose of the Study:

• To investigate the potential of polar (2)Σ paramagnetic molecules as qubits for quantum computing.
• To demonstrate tunable entanglement of molecular states using electric and magnetic fields.
• To propose and analyze schemes for implementing quantum gates with these molecules.

Main Methods:

• Utilizing Hund's case (b) free-rotor pair-eigenstates, which are inherently Bell states.
• Applying combinations of homogeneous and inhomogeneous electric and magnetic fields to control molecular states.
• Analyzing the feasibility of proposed quantum gate implementations considering spectral broadening and field inhomogeneities.

Main Results:

• Demonstrated that entanglement of Stark and Zeeman states in an array of polar (2)Σ molecules can be tuned.
• Showed that qubit sites can be addressed using tailored field configurations.
• Proposed two schemes for an optically controlled CNOT gate.

Conclusions:

• Polar (2)Σ paramagnetic molecules offer a viable route for quantum computation.
• Precise control over molecular entanglement is achievable with combined fields.
• The proposed CNOT gate schemes show potential, with feasibility discussed in light of experimental challenges.