  As quantum information technologies advance they face challenges in scaling
and connectivity. In particular, two necessities remain independent of the
technological implementation: the need for connectivity between distant qubits
and the need for efficient generation of entanglement. Perfect State Transfer
is a technique which realises the time optimal transfer of a quantum state
between distant nodes of qubit lattices with only nearest-neighbour couplings,
hence providing an important tool to improve device connectivity. Crucially,
the transfer protocol results in effective parity-dependent non-local
interactions, extending its utility to the efficient generation of entangled
states. Here, we experimentally demonstrate Perfect State Transfer and the
generation of multi-qubit entanglement on a chain of superconducting qubits.
The system consists of six fixed-frequency transmon qubits connected by tunable
couplers, where the couplings are controlled via parametric drives. By
simultaneously activating all couplings and engineering their individual
amplitudes and frequencies, we implement Perfect State Transfer on up to six
qubits and observe the respective single-excitation dynamics for different
initial states. We then apply the protocol in the presence of multiple
excitations and verify its parity-dependent property, where the number of
excitations within the chain controls the phase of the transferred state.
Finally, we utilise this property to prepare a multi-qubit
Greenberger-Horne-Zeilinger state using only a single transfer operation,
demonstrating its application for efficient entanglement generation.
