Experimental demonstration of a hyper-entangled ten-qubit Schr\"odinger cat state

TL;DR

This paper reports the experimental creation of hyper-entangled ten-qubit Schrödinger cat states using photons' polarization and momentum, advancing quantum state generation for quantum computing and metrology.

Contribution

It demonstrates the first creation of hyper-entangled ten-qubit Schrödinger cat states, expanding the capabilities of quantum state generation techniques.

Findings

Successfully generated hyper-entangled ten-qubit states

Measured high fidelities indicating genuine multi-partite entanglement

Method enables creation of various graph states up to ten qubits

Abstract

Coherent manipulation of an increasing number of qubits for the generation of entangled states has been an important goal and benchmark in the emerging field of quantum information science. The multiparticle entangled states serve as physical resources for measurement-based quantum computing and high-precision quantum metrology. However, their experimental preparation has proved extremely challenging. To date, entangled states up to six, eight atoms, or six photonic qubits have been demonstrated. Here, by exploiting both the photons' polarization and momentum degrees of freedom, we report the creation of hyper-entangled six-, eight-, and ten-qubit Schr\"odinger cat states. We characterize the cat states by evaluating their fidelities and detecting the presence of genuine multi-partite entanglement. Small modifications of the experimental setup will allow the generation of various graph states up to ten qubits. Our method provides a shortcut to expand the effective Hilbert space, opening up interesting applications such as quantum-enhanced super-resolving phase measurement, graph-state generation for anyonic simulation and topological error correction, and novel tests of nonlocality with hyper-entanglement.