Abstract:
It is a well-established fact that some quantum correlations are
nonlocal, meaning they cannot be described by a local hidden variable
model. Beyond this, certain quantum correlations are so strong that
they cannot be reproduced even if one allows only a small fraction of
the rounds to admit a local hidden variable description. Such
correlations are called fully nonlocal and they give rise to Bell
inequalities in which the quantum bound saturates the non-signaling
bound. A famous example is the Peres–Mermin square, in which the
underlying state is a four-dimensional maximally entangled state.
Surprisingly, examples of full nonlocality are rare and typically
restricted to maximally entangled states. In this work, we show that
in every local Hilbert space dimension d≥4 there exist non-maximally
entangled pure states that are fully nonlocal. In fact, we derive
simple criteria ensuring full nonlocality that depend only on the
smallest and largest Schmidt coefficients. Furthermore, we show that
all pure entangled states can be activated to exhibit full nonlocality
in the many-copy scenario.
Remote guests are invited via Zoom:
Zoom link:
https://us06web.zoom.us/j/84248911743?pwd=ZsiAOQbRgYCm5IFsArOnb18Fj5IsZh.1Meeting ID: 842 4891 1743
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