# From projected to observable-projected ensembles

- Institution: CERN
- Speaker: Sara Murciano
- Year: 2026
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3025659)
- Licence: [CERN](https://copyright.web.cern)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

Local measurements offer a powerful way to probe novel quantum phenomena, thermalization, and universal distributions in many-body quantum systems. In this talk, I will introduce the observable-projected ensemble, in which the subsystem state is conditioned on the outcome of measuring a single local Hermitian operator on part of its complement, rather than on a complete projective measurement of the whole complement. This protocol avoids the exponential complexity of conventional projected ensembles while remaining analytically tractable. I will discuss how its k-th moments compare with those of the Haar ensemble and show that, rather than approaching the Haar ensemble, the observable-projected ensemble can become exponentially distinguishable from it as the bath size grows. I will also describe its field-theoretic formulation in critical systems and illustrate the construction with the free compact boson.

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## Lectures

1. [From projected to observable-projected ensembles](https://invisiblenetwork.ai/learn/cern/3025659/83f71cbd6ec3), 1 h 8 min (CERN's player)