Related Experiment Video
Updated: Jun 27, 2025
12:19
Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source
Published on: April 4, 2017
8.4K
Experimental Demonstration of Input-Output Indefiniteness in a Single Quantum Device
Yu Guo1,2,3, Zixuan Liu4,5, Hao Tang1,2,3
1CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, 230026, China.
Physical Review Letters
|May 3, 2024
Summary
Researchers developed a method to detect indefinite input-output directions in quantum devices. This breakthrough in quantum information science has significant implications for photonic quantum technologies.
Area of Science:
- Quantum Physics
- Quantum Information Science
Background:
- Quantum theory permits information to traverse a single device in a coherent superposition of opposing directions.
- This leads to scenarios where the direction of information flow (input-output) is not definitively determined.
Purpose of the Study:
- To introduce a theoretical framework for detecting input-output indefiniteness in quantum systems.
- To experimentally validate this theoretical method using a photonic setup.
Main Methods:
- Development of a theoretical method to witness input-output indefiniteness.
- Experimental construction of a photonic device exhibiting this quantum phenomenon.
Main Results:
- The experiment successfully demonstrated input-output indefiniteness in a photonic setup.
- The observed effect achieved a statistical significance greater than 69 standard deviations.
Conclusions:
- The findings provide a method to characterize input-output indefiniteness as a valuable resource for quantum information processing.
- This work enables simulations of quantum indefiniteness in hypothetical scenarios, including the direction of time, using tabletop experiments.
Related Concept Videos
02:32The de Broglie Wavelength
25.9K
In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...
25.9K
02:45The Quantum-Mechanical Model of an Atom
42.3K
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.
42.3K
01:10Entropy Change in Reversible Processes
2.5K
In the Carnot engine, which achieves the maximum efficiency between two reservoirs of fixed temperatures, the total change in entropy is zero. The observation can be generalized by considering any reversible cyclic process consisting of many Carnot cycles. Thus, it can be stated that the total entropy change of any ideal reversible cycle is zero.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
2.5K
01:12Fermi Level Dynamics
244
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
244
03:25Free Energy Changes for Nonstandard States
11.4K
The free energy change for a process taking place with reactants and products present under nonstandard conditions (pressures other than 1 bar; concentrations other than 1 M) is related to the standard free energy change according to this equation:
where R is the gas constant (8.314 J/K·mol), T is the absolute temperature in kelvin, and Q is the reaction quotient. This equation may be used to predict the spontaneity of a process under any given set of conditions.
Reaction Quotient...
where R is the gas constant (8.314 J/K·mol), T is the absolute temperature in kelvin, and Q is the reaction quotient. This equation may be used to predict the spontaneity of a process under any given set of conditions.
Reaction Quotient...
11.4K