State transfer and entanglement between two-and four-level atoms in a cavity

Qudits with a large Hilbert space to host quantum information are widely utilized in various applications, such as quantum simulation and quantum computation, but the manipulation and scalability of qudits still face challenges. Here, we propose a scheme to directly and locally transfer quantum information from multiple atomic qubits to a single qudit and vice versa in an optical cavity. With the qubit–qudit interaction induced by the cavity, our scheme can transfer quantum states efficiently and measurement-independently. In addition, this scheme can robustly generate a high-dimensional maximal entangled state with asymmetric particle numbers, showing its potential in realizing an entanglement channel. Such an information interface for qubits and qudit may have enlightening significance for future research on quantum systems in hybrid dimensions.