  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, our scheme can transfer
quantum states efficiently and measurement-independently. In addition, this
scheme can be extended to the non-local case, where a high-dimensional maximal
entangled state with asymmetric particle numbers can be robustly generated for
realizing long-distance quantum communication. Such an information interface
for qubits and qudit may have enlightening significance for future research on
quantum systems in hybrid dimensions.
