Related Experiment Video
Updated: Mar 30, 2026
07:56
A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
9.1K
Full distribution of work done on a quantum system for arbitrary initial states
1SPIN-CNR, Via Dodecaneso 33, 16146 Genova, Italy.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|November 14, 2015
Summary
We present a new method to measure work and heat in quantum systems. Quantum coherence significantly impacts work statistics, offering insights into energy dynamics in driven and open quantum systems.
Area of Science:
- Quantum Thermodynamics
- Statistical Mechanics
- Quantum Measurement
Background:
- Understanding energy exchange (work, heat) in quantum systems is crucial.
- Existing methods often struggle with general quantum states and open systems.
- The role of quantum coherence in thermodynamic processes needs further clarification.
Purpose of the Study:
- To develop a general framework for defining and measuring work, internal energy, and dissipated heat in driven quantum systems.
- To investigate the impact of quantum coherence on the statistics of work done on a quantum system.
- To extend the framework for measuring heat dissipation in open quantum systems.
Main Methods:
- Introducing a physical detector naturally within the theoretical framework.
- Analyzing the statistics of work in the most general case, including quantum coherent states.
- Utilizing sequential coupling of the system to a detector to track energy dissipation.
Main Results:
- Demonstrated that quantum coherence in the initial state leads to measurable effects on work statistics.
- Recovered known results for systems starting in statistical mixtures of energy eigenstates.
- Showed the applicability of the method for measuring heat dissipated in open quantum systems.
Conclusions:
- The proposed approach provides a unified framework for studying thermodynamics in driven and open quantum systems.
- Quantum coherence plays a measurable role in the statistical properties of work.
- The method allows for tracking energy dissipation by only accessing system degrees of freedom.
Related Concept Videos
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
2.6K
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
2.6K
02:45The Quantum-Mechanical Model of an Atom
61.6K
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.
61.6K
02:39Entropy
37.9K
Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has expanded in a vacuum remains dispersed and never spontaneously reassembles. The unidirectional nature of these phenomena is the result of a thermodynamic state function called entropy (S). Entropy is the measure of the extent to which the energy is dispersed throughout a system, or in other words, it is proportional to the degree of disorder of a...
37.9K
01:18Entropy
3.8K
The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the entropy.
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
3.8K
01:03Atomic Nuclei: Nuclear Spin State Overview
2.2K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
2.2K
01:14The Entropy as a State Function
95
Consider an arbitrary process that moves between two specific states (A and B) in a cyclic manner. This process is reversible and broken down into smaller parts that each follow a Carnot cycle. A Carnot cycle has two isothermal (constant temperature) processes. During these processes, the ratio of the amount of heat transferred to their respective temperature remains constant. The other two processes in the Carnot cycle are also reversible but adiabatic, which means they occur without any heat...
95