The ATLAS Collaboration has achieved the highest-energy detection of quantum entanglement, a unique property of quantum mechanics, using the Large Hadron Collider (LHC). The team studied the effects of entanglement in top quarks, particles with a large mass and unique properties. The data were obtained from collisions at 13 TeV collected between 2015 and 2018, an energy scale significantly higher than typical laboratory experiments. This is the first-ever observation of entanglement between a pair of quarks and the highest-energy measurement of entanglement, potentially enabling the LHC to be used to study quantum information and foundational problems in quantum mechanics.
“It is so important, the 2022 Nobel Prize in Physics was awarded to Alain Aspect, John F. Clauser and Anton Zeilinger for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science.”
ATLAS Collaboration
Quantum Entanglement: A Crucial Difference Between Classical and Quantum Theories of Physics
Quantum entanglement is a unique property of quantum mechanics, where the state of one particle cannot be described independently from the other. This property is a key difference between classical and quantum theories of physics. In recognition of its importance, the 2022 Nobel Prize in Physics was awarded to Alain Aspect, John F. Clauser and Anton Zeilinger for their experiments with entangled photons, which established the violation of Bell inequalities and pioneered quantum information science.
The Mystery of the Top Quark’s Large Mass
The top quark, a particle with a mass greater than any other, is one of the most enduring mysteries of the Standard Model of physics. The reason for its large mass remains unexplained. However, the top quark has many unique properties that can be exploited. It is so heavy that it is extremely unstable and decays before it has time to hadronise, transferring all of its quantum numbers to its decay particles. Physicists can detect these decay particles and thus reconstruct the quantum state of a top quark, a feat that is impossible with any other quark. They can also measure its spin and use it to show that entanglement can be studied in top-quark-pair production at the Large Hadron Collider (LHC).
Quantum Entanglement at High Energies
Quantum entanglement has been measured in the past, but not at the energy scales achieved in this study. Most previous measurements involved low non-relativistic energies, typically using photons or electrons. The LHC, however, collides protons with an incredibly high centre-of-mass energy. The data used in this new measurement were obtained from collisions at 13 TeV collected between 2015 and 2018. This means researchers are delving into an energy scale over 12 orders of magnitude (a thousand billion times) higher than typical laboratory experiments.
First-Ever Observation of Quantum Entanglement Between a Pair of Quarks
In a new result, physicists studied the effects of entanglement in top quarks. They looked at top-quark pairs at their “production threshold”, i.e. when the invariant mass of the pair is at its minimum (approximately twice the mass of the top quark) and the top quarks are expected to be maximally entangled. The degree of entanglement is related to the angular distribution of the particles the top quarks decay into, giving physicists a direct way to study this quantum effect. As a result, they calculated the degree of entanglement at the particle level to be –0.547 ± 0.021, significantly lower than the minimum value indicative of a non-entangled state.
Implications for Quantum Information and Quantum Mechanics
This is the first-ever observation of entanglement between a pair of quarks and the highest-energy measurement of entanglement. Apart from the fundamental interest of testing quantum entanglement in a new environment, this measurement paves the way to use the LHC as a laboratory to study quantum information and other foundational problems in quantum mechanics.
- “The large mass of the top quark, which is greater than any other particle, remains one of the most enduring mysteries of the Standard Model. Why this is so remains unexplained. However, the top quark has many unique properties to exploit as a result.”
- “This is the first-ever observation of quantum entanglement between a pair of quarks and the highest-energy measurement of entanglement.”
- “Apart from the fundamental interest of testing quantum entanglement in a new environment, this measurement paves the way to use the LHC as a laboratory to study quantum information and other foundational problems in quantum mechanics.”
Summary
ATLAS is a general-purpose particle physics experiment at the Large Hadron Collider (LHC) at CERN. It is designed to exploit the full discovery potential of the LHC, pushing the frontiers of scientific knowledge.
Quantum entanglement, a unique property of quantum mechanics, has been observed for the first time between a pair of quarks, marking the highest-energy measurement of entanglement. This breakthrough tests quantum entanglement in a new environment and opens up possibilities for using the Large Hadron Collider as a laboratory to study quantum information and foundational problems in quantum mechanics.
- The ATLAS Collaboration has achieved the highest-energy detection of quantum entanglement, a unique property of quantum mechanics where the state of one particle cannot be described independently from another.
- This property was so significant that the 2022 Nobel Prize in Physics was awarded to Alain Aspect, John F. Clauser and Anton Zeilinger for their experiments with entangled photons.
- The ATLAS team used the top quark, the heaviest known particle, to study entanglement. The top quark’s unique properties, including its instability and quick decay, allowed physicists to reconstruct its quantum state and measure its spin.
- Previous entanglement measurements typically used photons or electrons at low non-relativistic energies. In contrast, the ATLAS experiment used data from proton collisions at the Large Hadron Collider (LHC) at an energy scale over 12 orders of magnitude higher than typical laboratory experiments.
- The ATLAS Collaboration’s findings represent the first-ever observation of quantum entanglement between a pair of quarks and the highest-energy measurement of entanglement. This opens up possibilities for using the LHC to study quantum information and other foundational problems in quantum mechanics.
