. Here, we experimentally demonstrate a scheme that amends the original measurement with additional modes in the form of ancillary photons, which leads to a more complex measurement pattern, and ultimately a higher success probability of

62.5\%

. Experimentally, we achieve a success probability of

(57.9 \pm 1.4)\%

, a significant improvement over the conventional scheme. With the possibility of extending the protocol to a larger number of ancillary photons, our work paves the way towards more efficient realisations of quantum technologies based on Bell-state measurements.

DOI: 10.18419/opus-14586

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50\%

62.5\%

. Experimentally, we achieve a success probability of

(57.9 \pm 1.4)\%

50\%

. Through using extra resources such as hyper entanglement, ancillary entanglement, and even a minimum amount of non-linearity complete Bell-state discrimination can be achieved. The success probability for Bell-like state discrimination is only

25\%

. We find that this can be boosted up to

50\%

using hyperentanglement in polarization, momentum, or OAM degrees of freedom of the photons which is in contrast to the Bell-state discrimination scenario where

100\%

can be achieved. Furthermore, we find that by using correlation in time of the photons all four Bell states can be distinguished with

100\%

success probability while for the Bell-like state discrimination, it strictly lies between

25\%

and

50\%

depending on the state parameter with only three Bell-like states being distinguishable. We also observe a similar contrast when we use ancillary entangled photons. While the success probability for all four Bell-state discrimination increases as

1-\frac{1}{2^N}

where N is the number of ancillary photons for Bell-like states it depends again on the state parameters and can be less than

25\%

in some cases. Also adding further ancillary photons decreases the success probability. We then show that using non-linear gadgets namely SFG

100\%

success probability can be achieved even for Bell-like state discrimination.

9/32

, and adaptive variants ensure that unsuccessful events project onto useful stabilizer states. We further show that the approach naturally generalizes to larger GHZ measurements, yielding an exponentially higher success probability than previous linear-optical schemes. Finally, we demonstrate practical advantages for graph-state resource generation, entanglement distribution between remote spin-photon interfaces, and fusion-based quantum computing. Our results establish high-efficiency many-body measurements as a new primitive for scalable photonic quantum information processing.