Dipolar-Coupled Entangled Molecular 4f Qubits.

We demonstrate by use of continuous wave- and pulse-electron paramagnetic resonance spectroscopy on oriented single crystals of magnetically dilute Yb III ions in Yb 0.01 Lu 0.99 (trensal) that molecular entangled two-qubit systems can be constructed by exploiting dipolar interactions between neighboring Yb III centers. Furthermore, we show that the phase memory time and Rabi frequencies of these dipolar-interaction-coupled entangled two-qubit systems are comparable to the ones of the corresponding single qubits.