Hyperentanglement --- simultaneous entanglement between multiple degrees offreedom of two or more systems --- has been used to enhance quantum informationtasks such as quantum communication and photonic quantum computing. Here weshow that hyperentanglement can lead to increased quantum advantage inmetrology, with contributions from the entanglement in each degree of freedom,allowing for Heisenberg scaling in the precision of parameter estimation. Ourexperiment employs photon pairs entangled in polarization and spatial degreesof freedom to estimate a small tilt angle of a mirror. Precision limits beyondshot noise are saturated through a simple binary measurement of thepolarization state. The broad validity of the dynamics considered here impliesthat similar strategies based on hyperentanglement can offer improvement in awide variety of metrological tasks.
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