Senior Researcher
Research Interests:
Quantum Entanglement and Bell inequalities violation at colliders
Selected publications:
Barr, A. J.; Fabbrichesi, M.; Floreanini, R.; Gabrielli, Emidio; Marzola, L.
Quantum entanglement and Bell inequality violation at colliders Journal Article
In: Progress in Particle and Nuclear Physics, vol. 139, 2024, ISSN: 0146-6410.
@article{Barr2024,
title = {Quantum entanglement and Bell inequality violation at colliders},
author = {A. J. Barr and M. Fabbrichesi and R. Floreanini and Emidio Gabrielli and L. Marzola},
doi = {10.1016/j.ppnp.2024.104134},
issn = {0146-6410},
journal = {Progress in Particle and Nuclear Physics},
volume = {139},
publisher = {Elsevier BV},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fabbrichesi, M.; Floreanini, R.; Gabrielli, Emidio; Marzola, L.
Bell inequality is violated in charmonium decays Journal Article
In: Phys. Rev. D, vol. 110, no. 5, 2024, ISSN: 2470-0029.
@article{Fabbrichesi2024b,
title = {Bell inequality is violated in charmonium decays},
author = {M. Fabbrichesi and R. Floreanini and Emidio Gabrielli and L. Marzola},
doi = {10.1103/physrevd.110.053008},
issn = {2470-0029},
journal = {Phys. Rev. D},
volume = {110},
number = {5},
publisher = {American Physical Society (APS)},
abstract = {<jats:p>The experimental data on the helicity amplitudes of charmonium decays allow us to measure entanglement in final state spin correlations and test possible violations of the Bell inequality. We find that the Bell inequality is violated with a significance of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>5</a:mn><a:mi>σ</a:mi></a:mrow></a:math> or more in the decays <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:msub><c:mrow><c:mi>η</c:mi></c:mrow><c:mrow><c:mi>c</c:mi></c:mrow></c:msub><c:mo>,</c:mo><c:msubsup><c:mrow><c:mi>χ</c:mi></c:mrow><c:mrow><c:mi>c</c:mi></c:mrow><c:mrow><c:mn>0</c:mn></c:mrow></c:msubsup><c:mo>,</c:mo><c:mi>J</c:mi><c:mo>/</c:mo><c:mi>ψ</c:mi><c:mo stretchy="false">→</c:mo><c:mi mathvariant="normal">Λ</c:mi><c:mo>+</c:mo><c:mover accent="true"><c:mrow><c:mi mathvariant="normal">Λ</c:mi></c:mrow><c:mrow><c:mo stretchy="false">¯</c:mo></c:mrow></c:mover></c:mrow></c:math>, <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mrow><j:mi>J</j:mi><j:mo>/</j:mo><j:mi>ψ</j:mi><j:mo stretchy="false">→</j:mo><j:msup><j:mrow><j:mi mathvariant="normal">Ξ</j:mi></j:mrow><j:mrow><j:mo>−</j:mo></j:mrow></j:msup><j:mo>+</j:mo><j:msup><j:mrow><j:mover accent="true"><j:mrow><j:mi mathvariant="normal">Ξ</j:mi></j:mrow><j:mrow><j:mo stretchy="false">¯</j:mo></j:mrow></j:mover></j:mrow><j:mrow><j:mo>+</j:mo></j:mrow></j:msup><j:mo>,</j:mo><j:msup><j:mrow><j:mi mathvariant="normal">Ξ</j:mi></j:mrow><j:mrow><j:mn>0</j:mn></j:mrow></j:msup><j:mo>+</j:mo><j:msup><j:mrow><j:mover accent="true"><j:mrow><j:mi mathvariant="normal">Ξ</j:mi></j:mrow><j:mrow><j:mo stretchy="false">¯</j:mo></j:mrow></j:mover></j:mrow><j:mrow><j:mn>0</j:mn></j:mrow></j:msup><j:mo>,</j:mo><j:msup><j:mrow><j:mi mathvariant="normal">Σ</j:mi></j:mrow><j:mrow><j:mo>−</j:mo></j:mrow></j:msup><j:mo>+</j:mo><j:msup><j:mrow><j:mover accent="true"><j:mrow><j:mi mathvariant="normal">Σ</j:mi></j:mrow><j:mrow><j:mo stretchy="false">¯</j:mo></j:mrow></j:mover></j:mrow><j:mrow><j:mo>+</j:mo></j:mrow></j:msup><j:mo>,</j:mo><j:msup><j:mrow><j:mi mathvariant="normal">Σ</j:mi></j:mrow><j:mrow><j:mn>0</j:mn></j:mrow></j:msup><j:mo>+</j:mo><j:msup><j:mrow><j:mover accent="true"><j:mrow><j:mi mathvariant="normal">Σ</j:mi></j:mrow><j:mrow><j:mo stretchy="false">¯</j:mo></j:mrow></j:mover></j:mrow><j:mrow><j:mn>0</j:mn></j:mrow></j:msup></j:mrow></j:math>, <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"><cb:mrow><cb:mi>ψ</cb:mi><cb:mo stretchy="false">(</cb:mo><cb:mn>3686</cb:mn><cb:mo stretchy="false">)</cb:mo><cb:mo stretchy="false">→</cb:mo><cb:msup><cb:mrow><cb:mi mathvariant="normal">Ξ</cb:mi></cb:mrow><cb:mrow><cb:mo>−</cb:mo></cb:mrow></cb:msup><cb:mo>+</cb:mo><cb:msup><cb:mrow><cb:mover accent="true"><cb:mrow><cb:mi mathvariant="normal">Ξ</cb:mi></cb:mrow><cb:mrow><cb:mo stretchy="false">¯</cb:mo></cb:mrow></cb:mover></cb:mrow><cb:mrow><cb:mo>+</cb:mo></cb:mrow></cb:msup><cb:mo>,</cb:mo><cb:msup><cb:mrow><cb:mi mathvariant="normal">Σ</cb:mi></cb:mrow><cb:mrow><cb:mo>−</cb:mo></cb:mrow></cb:msup><cb:mo>+</cb:mo><cb:msup><cb:mrow><cb:mover accent="true"><cb:mrow><cb:mi mathvariant="normal">Σ</cb:mi></cb:mrow><cb:mrow><cb:mo stretchy="false">¯</cb:mo></cb:mrow></cb:mover></cb:mrow><cb:mrow><cb:mo>+</cb:mo></cb:mrow></cb:msup><cb:mo>,</cb:mo><cb:msup><cb:mrow><cb:mi mathvariant="normal">Σ</cb:mi></cb:mrow><cb:mrow><cb:mn>0</cb:mn></cb:mrow></cb:msup><cb:mo>+</cb:mo><cb:msup><cb:mrow><cb:mover accent="true"><cb:mrow><cb:mi mathvariant="normal">Σ</cb:mi></cb:mrow><cb:mrow><cb:mo stretchy="false">¯</cb:mo></cb:mrow></cb:mover></cb:mrow><cb:mrow><cb:mn>0</cb:mn></cb:mrow></cb:msup></cb:mrow></cb:math>, <tb:math xmlns:tb="http://www.w3.org/1998/Math/MathML" display="inline"><tb:mrow><tb:msubsup><tb:mrow><tb:mi>χ</tb:mi></tb:mrow><tb:mrow><tb:mi>c</tb:mi></tb:mrow><tb:mrow><tb:mn>0</tb:mn></tb:mrow></tb:msubsup><tb:mo>,</tb:mo><tb:msubsup><tb:mrow><tb:mi>χ</tb:mi></tb:mrow><tb:mrow><tb:mi>c</tb:mi></tb:mrow><tb:mrow><tb:mn>1</tb:mn></tb:mrow></tb:msubsup><tb:mo stretchy="false">→</tb:mo><tb:mi>ϕ</tb:mi><tb:mo>+</tb:mo><tb:mi>ϕ</tb:mi></tb:mrow></tb:math>. The decays <wb:math xmlns:wb="http://www.w3.org/1998/Math/MathML" display="inline"><wb:mi>ψ</wb:mi><wb:mo stretchy="false">(</wb:mo><wb:mn>3686</wb:mn><wb:mo stretchy="false">)</wb:mo><wb:mo stretchy="false">→</wb:mo><wb:mi mathvariant="normal">Λ</wb:mi><wb:mo>+</wb:mo><wb:mover accent="true"><wb:mi mathvariant="normal">Λ</wb:mi><wb:mo stretchy="false">¯</wb:mo></wb:mover></wb:math> and <fc:math xmlns:fc="http://www.w3.org/1998/Math/MathML" display="inline"><fc:msup><fc:mi mathvariant="normal">Ξ</fc:mi><fc:mn>0</fc:mn></fc:msup><fc:mo>+</fc:mo><fc:msup><fc:mover accent="true"><fc:mi mathvariant="normal">Ξ</fc:mi><fc:mo stretchy="false">¯</fc:mo></fc:mover><fc:mn>0</fc:mn></fc:msup></fc:math> show the same violation but with less significance. The decay <lc:math xmlns:lc="http://www.w3.org/1998/Math/MathML" display="inline"><lc:mrow><lc:mi>ψ</lc:mi><lc:mo stretchy="false">(</lc:mo><lc:mn>3686</lc:mn><lc:mo stretchy="false">)</lc:mo><lc:mo stretchy="false">→</lc:mo><lc:msup><lc:mrow><lc:mi mathvariant="normal">Ω</lc:mi></lc:mrow><lc:mrow><lc:mo>−</lc:mo></lc:mrow></lc:msup><lc:mo>+</lc:mo><lc:msup><lc:mrow><lc:mover accent="true"><lc:mrow><lc:mi mathvariant="normal">Ω</lc:mi></lc:mrow><lc:mrow><lc:mo stretchy="false">¯</lc:mo></lc:mrow></lc:mover></lc:mrow><lc:mrow><lc:mo>+</lc:mo></lc:mrow></lc:msup></lc:mrow></lc:math> displays entanglement. These results firmly establish the presence of entanglement and quantum nonseparability at high energies, in a setting with particles of different spins and interacting through electroweak and strong interactions. In addition, the relatively long lifetime of some of the strange baryons produced in the decays provides a natural probe to test whether quantum spin correlations remain after the particles have interacted with the beam pipe and the first few layers of the detector.</jats:p>
<jats:sec>
<jats:title/>
<jats:supplementary-material>
<jats:permissions>
<jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>
<jats:copyright-year>2024</jats:copyright-year>
</jats:permissions>
</jats:supplementary-material>
</jats:sec>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:p>The experimental data on the helicity amplitudes of charmonium decays allow us to measure entanglement in final state spin correlations and test possible violations of the Bell inequality. We find that the Bell inequality is violated with a significance of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>5</a:mn><a:mi>σ</a:mi></a:mrow></a:math> or more in the decays <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:msub><c:mrow><c:mi>η</c:mi></c:mrow><c:mrow><c:mi>c</c:mi></c:mrow></c:msub><c:mo>,</c:mo><c:msubsup><c:mrow><c:mi>χ</c:mi></c:mrow><c:mrow><c:mi>c</c:mi></c:mrow><c:mrow><c:mn>0</c:mn></c:mrow></c:msubsup><c:mo>,</c:mo><c:mi>J</c:mi><c:mo>/</c:mo><c:mi>ψ</c:mi><c:mo stretchy="false">→</c:mo><c:mi mathvariant="normal">Λ</c:mi><c:mo>+</c:mo><c:mover accent="true"><c:mrow><c:mi mathvariant="normal">Λ</c:mi></c:mrow><c:mrow><c:mo stretchy="false">¯</c:mo></c:mrow></c:mover></c:mrow></c:math>, <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mrow><j:mi>J</j:mi><j:mo>/</j:mo><j:mi>ψ</j:mi><j:mo stretchy="false">→</j:mo><j:msup><j:mrow><j:mi mathvariant="normal">Ξ</j:mi></j:mrow><j:mrow><j:mo>−</j:mo></j:mrow></j:msup><j:mo>+</j:mo><j:msup><j:mrow><j:mover accent="true"><j:mrow><j:mi mathvariant="normal">Ξ</j:mi></j:mrow><j:mrow><j:mo stretchy="false">¯</j:mo></j:mrow></j:mover></j:mrow><j:mrow><j:mo>+</j:mo></j:mrow></j:msup><j:mo>,</j:mo><j:msup><j:mrow><j:mi mathvariant="normal">Ξ</j:mi></j:mrow><j:mrow><j:mn>0</j:mn></j:mrow></j:msup><j:mo>+</j:mo><j:msup><j:mrow><j:mover accent="true"><j:mrow><j:mi mathvariant="normal">Ξ</j:mi></j:mrow><j:mrow><j:mo stretchy="false">¯</j:mo></j:mrow></j:mover></j:mrow><j:mrow><j:mn>0</j:mn></j:mrow></j:msup><j:mo>,</j:mo><j:msup><j:mrow><j:mi mathvariant="normal">Σ</j:mi></j:mrow><j:mrow><j:mo>−</j:mo></j:mrow></j:msup><j:mo>+</j:mo><j:msup><j:mrow><j:mover accent="true"><j:mrow><j:mi mathvariant="normal">Σ</j:mi></j:mrow><j:mrow><j:mo stretchy="false">¯</j:mo></j:mrow></j:mover></j:mrow><j:mrow><j:mo>+</j:mo></j:mrow></j:msup><j:mo>,</j:mo><j:msup><j:mrow><j:mi mathvariant="normal">Σ</j:mi></j:mrow><j:mrow><j:mn>0</j:mn></j:mrow></j:msup><j:mo>+</j:mo><j:msup><j:mrow><j:mover accent="true"><j:mrow><j:mi mathvariant="normal">Σ</j:mi></j:mrow><j:mrow><j:mo stretchy="false">¯</j:mo></j:mrow></j:mover></j:mrow><j:mrow><j:mn>0</j:mn></j:mrow></j:msup></j:mrow></j:math>, <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"><cb:mrow><cb:mi>ψ</cb:mi><cb:mo stretchy="false">(</cb:mo><cb:mn>3686</cb:mn><cb:mo stretchy="false">)</cb:mo><cb:mo stretchy="false">→</cb:mo><cb:msup><cb:mrow><cb:mi mathvariant="normal">Ξ</cb:mi></cb:mrow><cb:mrow><cb:mo>−</cb:mo></cb:mrow></cb:msup><cb:mo>+</cb:mo><cb:msup><cb:mrow><cb:mover accent="true"><cb:mrow><cb:mi mathvariant="normal">Ξ</cb:mi></cb:mrow><cb:mrow><cb:mo stretchy="false">¯</cb:mo></cb:mrow></cb:mover></cb:mrow><cb:mrow><cb:mo>+</cb:mo></cb:mrow></cb:msup><cb:mo>,</cb:mo><cb:msup><cb:mrow><cb:mi mathvariant="normal">Σ</cb:mi></cb:mrow><cb:mrow><cb:mo>−</cb:mo></cb:mrow></cb:msup><cb:mo>+</cb:mo><cb:msup><cb:mrow><cb:mover accent="true"><cb:mrow><cb:mi mathvariant="normal">Σ</cb:mi></cb:mrow><cb:mrow><cb:mo stretchy="false">¯</cb:mo></cb:mrow></cb:mover></cb:mrow><cb:mrow><cb:mo>+</cb:mo></cb:mrow></cb:msup><cb:mo>,</cb:mo><cb:msup><cb:mrow><cb:mi mathvariant="normal">Σ</cb:mi></cb:mrow><cb:mrow><cb:mn>0</cb:mn></cb:mrow></cb:msup><cb:mo>+</cb:mo><cb:msup><cb:mrow><cb:mover accent="true"><cb:mrow><cb:mi mathvariant="normal">Σ</cb:mi></cb:mrow><cb:mrow><cb:mo stretchy="false">¯</cb:mo></cb:mrow></cb:mover></cb:mrow><cb:mrow><cb:mn>0</cb:mn></cb:mrow></cb:msup></cb:mrow></cb:math>, <tb:math xmlns:tb="http://www.w3.org/1998/Math/MathML" display="inline"><tb:mrow><tb:msubsup><tb:mrow><tb:mi>χ</tb:mi></tb:mrow><tb:mrow><tb:mi>c</tb:mi></tb:mrow><tb:mrow><tb:mn>0</tb:mn></tb:mrow></tb:msubsup><tb:mo>,</tb:mo><tb:msubsup><tb:mrow><tb:mi>χ</tb:mi></tb:mrow><tb:mrow><tb:mi>c</tb:mi></tb:mrow><tb:mrow><tb:mn>1</tb:mn></tb:mrow></tb:msubsup><tb:mo stretchy="false">→</tb:mo><tb:mi>ϕ</tb:mi><tb:mo>+</tb:mo><tb:mi>ϕ</tb:mi></tb:mrow></tb:math>. The decays <wb:math xmlns:wb="http://www.w3.org/1998/Math/MathML" display="inline"><wb:mi>ψ</wb:mi><wb:mo stretchy="false">(</wb:mo><wb:mn>3686</wb:mn><wb:mo stretchy="false">)</wb:mo><wb:mo stretchy="false">→</wb:mo><wb:mi mathvariant="normal">Λ</wb:mi><wb:mo>+</wb:mo><wb:mover accent="true"><wb:mi mathvariant="normal">Λ</wb:mi><wb:mo stretchy="false">¯</wb:mo></wb:mover></wb:math> and <fc:math xmlns:fc="http://www.w3.org/1998/Math/MathML" display="inline"><fc:msup><fc:mi mathvariant="normal">Ξ</fc:mi><fc:mn>0</fc:mn></fc:msup><fc:mo>+</fc:mo><fc:msup><fc:mover accent="true"><fc:mi mathvariant="normal">Ξ</fc:mi><fc:mo stretchy="false">¯</fc:mo></fc:mover><fc:mn>0</fc:mn></fc:msup></fc:math> show the same violation but with less significance. The decay <lc:math xmlns:lc="http://www.w3.org/1998/Math/MathML" display="inline"><lc:mrow><lc:mi>ψ</lc:mi><lc:mo stretchy="false">(</lc:mo><lc:mn>3686</lc:mn><lc:mo stretchy="false">)</lc:mo><lc:mo stretchy="false">→</lc:mo><lc:msup><lc:mrow><lc:mi mathvariant="normal">Ω</lc:mi></lc:mrow><lc:mrow><lc:mo>−</lc:mo></lc:mrow></lc:msup><lc:mo>+</lc:mo><lc:msup><lc:mrow><lc:mover accent="true"><lc:mrow><lc:mi mathvariant="normal">Ω</lc:mi></lc:mrow><lc:mrow><lc:mo stretchy="false">¯</lc:mo></lc:mrow></lc:mover></lc:mrow><lc:mrow><lc:mo>+</lc:mo></lc:mrow></lc:msup></lc:mrow></lc:math> displays entanglement. These results firmly establish the presence of entanglement and quantum nonseparability at high energies, in a setting with particles of different spins and interacting through electroweak and strong interactions. In addition, the relatively long lifetime of some of the strange baryons produced in the decays provides a natural probe to test whether quantum spin correlations remain after the particles have interacted with the beam pipe and the first few layers of the detector.</jats:p>
<jats:sec>
<jats:title/>
<jats:supplementary-material>
<jats:permissions>
<jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>
<jats:copyright-year>2024</jats:copyright-year>
</jats:permissions>
</jats:supplementary-material>
</jats:sec>
<jats:sec>
<jats:title/>
<jats:supplementary-material>
<jats:permissions>
<jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>
<jats:copyright-year>2024</jats:copyright-year>
</jats:permissions>
</jats:supplementary-material>
</jats:sec>
Fabbrichesi, M.; Floreanini, R.; Gabrielli, Emidio; Marzola, L.
Bell inequality is violated in B0-->J/PSI K*(892) decays Journal Article
In: Phys. Rev. D, vol. 109, no. 3, 2024, ISSN: 2470-0029.
@article{Fabbrichesi2024,
title = {Bell inequality is violated in B0-->J/PSI K*(892) decays},
author = {M. Fabbrichesi and R. Floreanini and Emidio Gabrielli and L. Marzola},
doi = {10.1103/physrevd.109.l031104},
issn = {2470-0029},
journal = {Phys. Rev. D},
volume = {109},
number = {3},
publisher = {American Physical Society (APS)},
abstract = {The violation of the Bell inequality is one of the hallmarks of quantum mechanics and can be used to rule out local deterministic alternative descriptions. We utilize the data analysis published by the LHCb Collaboration on the helicity amplitudes for the decay to compute the entanglement among the polarizations of the final vector mesons and the violation of the Bell inequality that it entails. We find that quantum entanglement can be detected with a significance well above and Bell inequality is violated with a significance well above (nominally —thereby firmly establishing these distinguishing feature of quantum mechanics at high energies in a collider setting and in the presence of strong and weak interactions. Entanglement is also present and the Bell inequality is violated in other decays of the mesons into vector mesons, but with lesser significance.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The violation of the Bell inequality is one of the hallmarks of quantum mechanics and can be used to rule out local deterministic alternative descriptions. We utilize the data analysis published by the LHCb Collaboration on the helicity amplitudes for the decay to compute the entanglement among the polarizations of the final vector mesons and the violation of the Bell inequality that it entails. We find that quantum entanglement can be detected with a significance well above and Bell inequality is violated with a significance well above (nominally —thereby firmly establishing these distinguishing feature of quantum mechanics at high energies in a collider setting and in the presence of strong and weak interactions. Entanglement is also present and the Bell inequality is violated in other decays of the mesons into vector mesons, but with lesser significance.
Fabbrichesi, M.; Floreanini, R.; Gabrielli, Emidio; Marzola, L.
Bell inequalities and quantum entanglement in weak gauge boson production at the LHC and future colliders Journal Article
In: Eur. Phys. J. C, vol. 83, no. 9, 2023, ISSN: 1434-6052.
@article{Fabbrichesi2023b,
title = {Bell inequalities and quantum entanglement in weak gauge boson production at the LHC and future colliders},
author = {M. Fabbrichesi and R. Floreanini and Emidio Gabrielli and L. Marzola},
doi = {10.1140/epjc/s10052-023-11935-8},
issn = {1434-6052},
journal = {Eur. Phys. J. C},
volume = {83},
number = {9},
publisher = {Springer Science and Business Media LLC},
abstract = {<jats:title>Abstract</jats:title><jats:p>Quantum entanglement of weak interaction gauge bosons produced at colliders can be explored by computing the corresponding polarization density matrix. To this end, we consider the Higgs boson decays <jats:inline-formula><jats:alternatives><jats:tex-math>$$Hrightarrow W W^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>W</mml:mi>
<mml:msup>
<mml:mi>W</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> and <jats:inline-formula><jats:alternatives><jats:tex-math>$$Hrightarrow Z Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>Z</mml:mi>
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula>, in which <jats:inline-formula><jats:alternatives><jats:tex-math>$$W^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msup>
<mml:mi>W</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:math></jats:alternatives></jats:inline-formula> and <jats:inline-formula><jats:alternatives><jats:tex-math>$$Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:math></jats:alternatives></jats:inline-formula> are off-shell states, and the <jats:italic>WW</jats:italic>, <jats:italic>WZ</jats:italic> and <jats:italic>ZZ</jats:italic> di-boson production in proton collisions. The polarization density matrix of the di-boson state is determined by the amplitude of the production process and can be experimentally reconstructed from the angular distribution of the momenta of the final states into which the gauge bosons decay. We show that a suitable instance of the Bell inequality is violated in <jats:inline-formula><jats:alternatives><jats:tex-math>$$Hrightarrow Z Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>Z</mml:mi>
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> to a degree that can be tested at the LHC with future data. The same Bell inequality is violated in the production of <jats:italic>WW</jats:italic> and <jats:italic>ZZ</jats:italic> boson pairs for invariant masses above 900 GeV and scattering angles close to <jats:inline-formula><jats:alternatives><jats:tex-math>$$pi /2$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>π</mml:mi>
<mml:mo>/</mml:mo>
<mml:mn>2</mml:mn>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> in the center of mass frame. LHC data in this case are not sufficient to establish the violation of the Bell inequality. We also analyze the prospects for detecting Bell inequality violations in di-boson final states at future <jats:inline-formula><jats:alternatives><jats:tex-math>$$e^+e^-$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:msup>
<mml:mi>e</mml:mi>
<mml:mo>+</mml:mo>
</mml:msup>
<mml:msup>
<mml:mi>e</mml:mi>
<mml:mo>-</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> and muon colliders. A further observable that provides a lower bound on the amount of polarization entanglement in the di-boson system is computed for each of the examined processes. The analytic expressions for the polarization density matrices are presented in full in an Appendix. We also provide the unitary matrices required in the optimization procedure necessary in testing the Bell inequalities.</jats:p>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:title>Abstract</jats:title><jats:p>Quantum entanglement of weak interaction gauge bosons produced at colliders can be explored by computing the corresponding polarization density matrix. To this end, we consider the Higgs boson decays <jats:inline-formula><jats:alternatives><jats:tex-math>$$Hrightarrow W W^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>W</mml:mi>
<mml:msup>
<mml:mi>W</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> and <jats:inline-formula><jats:alternatives><jats:tex-math>$$Hrightarrow Z Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>Z</mml:mi>
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula>, in which <jats:inline-formula><jats:alternatives><jats:tex-math>$$W^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msup>
<mml:mi>W</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:math></jats:alternatives></jats:inline-formula> and <jats:inline-formula><jats:alternatives><jats:tex-math>$$Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:math></jats:alternatives></jats:inline-formula> are off-shell states, and the <jats:italic>WW</jats:italic>, <jats:italic>WZ</jats:italic> and <jats:italic>ZZ</jats:italic> di-boson production in proton collisions. The polarization density matrix of the di-boson state is determined by the amplitude of the production process and can be experimentally reconstructed from the angular distribution of the momenta of the final states into which the gauge bosons decay. We show that a suitable instance of the Bell inequality is violated in <jats:inline-formula><jats:alternatives><jats:tex-math>$$Hrightarrow Z Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>Z</mml:mi>
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> to a degree that can be tested at the LHC with future data. The same Bell inequality is violated in the production of <jats:italic>WW</jats:italic> and <jats:italic>ZZ</jats:italic> boson pairs for invariant masses above 900 GeV and scattering angles close to <jats:inline-formula><jats:alternatives><jats:tex-math>$$pi /2$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>π</mml:mi>
<mml:mo>/</mml:mo>
<mml:mn>2</mml:mn>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> in the center of mass frame. LHC data in this case are not sufficient to establish the violation of the Bell inequality. We also analyze the prospects for detecting Bell inequality violations in di-boson final states at future <jats:inline-formula><jats:alternatives><jats:tex-math>$$e^+e^-$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:msup>
<mml:mi>e</mml:mi>
<mml:mo>+</mml:mo>
</mml:msup>
<mml:msup>
<mml:mi>e</mml:mi>
<mml:mo>-</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> and muon colliders. A further observable that provides a lower bound on the amount of polarization entanglement in the di-boson system is computed for each of the examined processes. The analytic expressions for the polarization density matrices are presented in full in an Appendix. We also provide the unitary matrices required in the optimization procedure necessary in testing the Bell inequalities.</jats:p>
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>W</mml:mi>
<mml:msup>
<mml:mi>W</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> and <jats:inline-formula><jats:alternatives><jats:tex-math>$$Hrightarrow Z Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>Z</mml:mi>
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula>, in which <jats:inline-formula><jats:alternatives><jats:tex-math>$$W^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msup>
<mml:mi>W</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:math></jats:alternatives></jats:inline-formula> and <jats:inline-formula><jats:alternatives><jats:tex-math>$$Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:math></jats:alternatives></jats:inline-formula> are off-shell states, and the <jats:italic>WW</jats:italic>, <jats:italic>WZ</jats:italic> and <jats:italic>ZZ</jats:italic> di-boson production in proton collisions. The polarization density matrix of the di-boson state is determined by the amplitude of the production process and can be experimentally reconstructed from the angular distribution of the momenta of the final states into which the gauge bosons decay. We show that a suitable instance of the Bell inequality is violated in <jats:inline-formula><jats:alternatives><jats:tex-math>$$Hrightarrow Z Z^*$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>H</mml:mi>
<mml:mo>→</mml:mo>
<mml:mi>Z</mml:mi>
<mml:msup>
<mml:mi>Z</mml:mi>
<mml:mo>∗</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> to a degree that can be tested at the LHC with future data. The same Bell inequality is violated in the production of <jats:italic>WW</jats:italic> and <jats:italic>ZZ</jats:italic> boson pairs for invariant masses above 900 GeV and scattering angles close to <jats:inline-formula><jats:alternatives><jats:tex-math>$$pi /2$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:mi>π</mml:mi>
<mml:mo>/</mml:mo>
<mml:mn>2</mml:mn>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> in the center of mass frame. LHC data in this case are not sufficient to establish the violation of the Bell inequality. We also analyze the prospects for detecting Bell inequality violations in di-boson final states at future <jats:inline-formula><jats:alternatives><jats:tex-math>$$e^+e^-$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mrow>
<mml:msup>
<mml:mi>e</mml:mi>
<mml:mo>+</mml:mo>
</mml:msup>
<mml:msup>
<mml:mi>e</mml:mi>
<mml:mo>-</mml:mo>
</mml:msup>
</mml:mrow>
</mml:math></jats:alternatives></jats:inline-formula> and muon colliders. A further observable that provides a lower bound on the amount of polarization entanglement in the di-boson system is computed for each of the examined processes. The analytic expressions for the polarization density matrices are presented in full in an Appendix. We also provide the unitary matrices required in the optimization procedure necessary in testing the Bell inequalities.</jats:p>
Fabbrichesi, M.; Floreanini, R.; Gabrielli, Emidio
Constraining new physics in entangled two-qubit systems: top-quark, tau-lepton and photon pairs Journal Article
In: Eur. Phys. J. C, vol. 83, no. 2, 2023, ISSN: 1434-6052.
@article{Fabbrichesi2023,
title = {Constraining new physics in entangled two-qubit systems: top-quark, tau-lepton and photon pairs},
author = {M. Fabbrichesi and R. Floreanini and Emidio Gabrielli},
doi = {10.1140/epjc/s10052-023-11307-2},
issn = {1434-6052},
journal = {Eur. Phys. J. C},
volume = {83},
number = {2},
publisher = {Springer Science and Business Media LLC},
abstract = {<jats:title>Abstract</jats:title><jats:p>The measurement of quantum entanglement can provide a new and most sensitive probe to physics beyond the Standard Model. We use the concurrence of the top-quark pair spin states produced at colliders to constrain the magnetic dipole term in the coupling between top quark and gluons, that of <jats:inline-formula><jats:alternatives><jats:tex-math>$$tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pair spin states to bound contact interactions and that of <jats:inline-formula><jats:alternatives><jats:tex-math>$$tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pairs or two-photons spin states from the decay of the Higgs boson in trying to distinguish between CP-even and odd couplings. These four examples show the power of the new approach as well as its limitations. We show that differences in the entanglement in the top-quark and <jats:inline-formula><jats:alternatives><jats:tex-math>$$tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pair production cross sections can provide constraints better than those previously estimated from total cross sections or classical correlations. Instead, the final states in the decays of the Higgs boson remain maximally entangled even in the presence of CP-odd couplings and cannot be used to set bounds on new physics. We discuss the violation of Bell inequalities featured in all four processes.</jats:p>},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
<jats:title>Abstract</jats:title><jats:p>The measurement of quantum entanglement can provide a new and most sensitive probe to physics beyond the Standard Model. We use the concurrence of the top-quark pair spin states produced at colliders to constrain the magnetic dipole term in the coupling between top quark and gluons, that of <jats:inline-formula><jats:alternatives><jats:tex-math>$$tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pair spin states to bound contact interactions and that of <jats:inline-formula><jats:alternatives><jats:tex-math>$$tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pairs or two-photons spin states from the decay of the Higgs boson in trying to distinguish between CP-even and odd couplings. These four examples show the power of the new approach as well as its limitations. We show that differences in the entanglement in the top-quark and <jats:inline-formula><jats:alternatives><jats:tex-math>$$tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pair production cross sections can provide constraints better than those previously estimated from total cross sections or classical correlations. Instead, the final states in the decays of the Higgs boson remain maximally entangled even in the presence of CP-odd couplings and cannot be used to set bounds on new physics. We discuss the violation of Bell inequalities featured in all four processes.</jats:p>
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pair spin states to bound contact interactions and that of <jats:inline-formula><jats:alternatives><jats:tex-math>$$tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pairs or two-photons spin states from the decay of the Higgs boson in trying to distinguish between CP-even and odd couplings. These four examples show the power of the new approach as well as its limitations. We show that differences in the entanglement in the top-quark and <jats:inline-formula><jats:alternatives><jats:tex-math>$$tau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">
<mml:mi>τ</mml:mi>
</mml:math></jats:alternatives></jats:inline-formula>-lepton pair production cross sections can provide constraints better than those previously estimated from total cross sections or classical correlations. Instead, the final states in the decays of the Higgs boson remain maximally entangled even in the presence of CP-odd couplings and cannot be used to set bounds on new physics. We discuss the violation of Bell inequalities featured in all four processes.</jats:p>
Biography
Graduated in Physics at the University of Rome "La Sapienza" (1986). In 1991 he received his PhD at the University of Rome "La Sapienza". He hold several postdoc and senior scientist/faculty positions in various Universities and research institutes abroad. Since 2012 is Associate Professor at the Physics Department of the University of Trieste.