Related Experiment Video
Updated: Oct 11, 2025
07:56
A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
8.7K
Observers of quantum systems cannot agree to disagree
Patricia Contreras-Tejada1, Giannicola Scarpa2, Aleksander M Kubicki3
1Instituto de Ciencias Matemáticas, 28049, Madrid, Spain.
Nature Communications
|December 3, 2021
Summary
This study explores if observer agreement is a physical principle. It extends the Agreement Theorem to quantum systems, finding that some post-quantum theories allow observers to "agree to disagree." This links quantum information and epistemology.
Area of Science:
- Quantum foundations
- Epistemics
- Quantum information theory
Background:
- Active research in quantum foundations seeks constraints to rule out post-quantum theories.
- Aumann's Agreement Theorem states classical observers cannot agree to disagree.
Purpose of the Study:
- To investigate if observer agreement can be a physical principle for any theory of the world.
- To extend the Agreement Theorem to no-signaling settings and quantum systems.
Main Methods:
- Extension of Aumann's Agreement Theorem to no-signaling scenarios.
- Construction of post-quantum no-signaling boxes to demonstrate agreement to disagree.
Main Results:
- An Agreement Theorem is established for observers of quantum systems.
- Examples of post-quantum no-signaling boxes are constructed where observers can agree to disagree.
- The PR box is identified as an extremal instance of this phenomenon.
Conclusions:
- Observer agreement may be a physical principle.
- The study establishes links between epistemology and quantum information, warranting further exploration.
Related Concept Videos
02:45The Quantum-Mechanical Model of an Atom
52.7K
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra.
52.7K
04:08The Uncertainty Principle
28.4K
Werner Heisenberg considered the limits of how accurately one can measure properties of an electron or other microscopic particles. He determined that there is a fundamental limit to how accurately one can measure both a particle’s position and its momentum simultaneously. The more accurate the measurement of the momentum of a particle is known, the less accurate the position at that time is known and vice versa. This is what is now called the Heisenberg uncertainty principle. He...
28.4K
03:06The Pauli Exclusion Principle
54.8K
The arrangement of electrons in the orbitals of an atom is called its electron configuration. We describe an electron configuration with a symbol that contains three pieces of information:
54.8K
01:10First Law: Particles in One-dimensional Equilibrium
7.2K
Newton's first law of motion states that a body at rest remains at rest, or if in motion, remains in motion at constant velocity, unless acted on by a net external force. It also states that there must be a cause for any change in velocity (a change in either magnitude or direction) to occur. This cause is a net external force. For example, consider what happens to an object sliding along a rough horizontal surface. The object quickly grinds to a halt, due to the net force of friction. If...
7.2K
01:18First Law: Particles in Two-dimensional Equilibrium
6.7K
Recall that a particle in equilibrium is one for which the external forces are balanced. Static equilibrium involves objects at rest, and dynamic equilibrium involves objects in motion without acceleration; but it is important to remember that these conditions are relative. For instance, an object may be at rest when viewed from one frame of reference, but that same object would appear to be in motion when viewed by someone moving at a constant velocity.
Newton's first law tells us about...
Newton's first law tells us about...
6.7K
01:23Stability of Equilibrium Configuration
562
Understanding the stability of equilibrium configurations is a fundamental part of mechanical engineering. In any system, there are three distinct types of equilibrium: stable, neutral, and unstable.
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
562