Related Experiment Video
Updated: Jul 13, 2026
11:21
Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Driven spin systems as quantum thermodynamic machines: fundamental limits
Markus J Henrich1, Günter Mahler, Mathias Michel
1Institute of Theoretical Physics I, University of Stuttgart, Pfaffenwaldring 57, Stuttgart, Germany. markus.henrich@itp1.uni-stuttgart.de
Summary
Coupled quantum systems, like qubits, can function as thermodynamic machines. Arranging at least three qubits in a chain allows them to operate as heat pumps or engines, with efficiency dependent on temperature and energy differences.
Area of Science:
- Quantum thermodynamics
- Quantum information processing
- Spin systems
Background:
- Quantum systems, particularly qubits, are fundamental to quantum information processing.
- Thermodynamic machines operate based on heat transfer and work extraction.
- Understanding quantum behavior at thermodynamic scales is an active research area.
Purpose of the Study:
- To investigate the potential of coupled two-level systems (qubits) as thermodynamic machines.
- To determine the minimum requirements for such a quantum thermodynamic machine.
- To analyze the operational modes (heat pump or engine) and efficiency factors.
Main Methods:
- Modeling coupled two-level systems (qubits) arranged in a chain.
- Interfacing the system between two thermal baths with a temperature difference (DeltaT).
- Applying external driving to a central working spin.
- Analyzing Carnot-type thermodynamic cycles.
Main Results:
- A minimum of three coupled qubits arranged in a chain is necessary.
- The quantum system can operate as either a heat pump or a heat engine.
- The machine's performance is dependent on the temperature difference between baths (DeltaT) and the energy difference in the spin system (DeltaE).
Conclusions:
- Coupled qubits can be engineered into functional thermodynamic machines.
- The efficiency of these quantum machines is tunable via DeltaT and DeltaE.
- This work bridges quantum information processing and quantum thermodynamics.
Related Concept Videos
01:22Limits of the First Law of Thermodynamics
Spontaneous processes, like a rock falling to the ground or sodium reacting with chlorine, occur without external work and often involve a decrease in the system‘s energy. However, certain endothermic processes, such as the dissolution of sodium chloride in water, occur spontaneously even though they increase the energy of the system. This limitation suggests that the First Law of Thermodynamics, which states that the total energy of a system is constant in an isolated system, cannot fully...
01:06Thermodynamic Systems
A thermodynamic system is a set of objects whose thermodynamic properties are of interest. The system is considered to be embedded in its surroundings or the environment. The system and its environment can exchange heat and do work on each other through a boundary that separates them. However, the immediate surroundings of the system interact with it directly and therefore have a much stronger influence on its behavior and properties.
Consider an example of tea boiling in a kettle. The tea and...
Consider an example of tea boiling in a kettle. The tea and...
01:15Statements of the Second Law of Thermodynamics
The second law of thermodynamics can be stated in several different ways, and all of them can be shown to imply the others. The Clausius’ statement of the second law of thermodynamics is based on the irreversibility of spontaneous heat flow. It states that heat will not flow from the colder body to the hotter body unless some other process is involved. Additionally, as per the Kelvin’s statement, it is impossible to convert the heat from a single source into work without any other effect. This...
02:38Third Law of Thermodynamics
A pure, perfectly crystalline solid possessing no kinetic energy (that is, at a temperature of absolute zero, 0 K) may be described by a single microstate, as its purity, perfect crystallinity,and complete lack of motion means there is but one possible location for each identical atom or molecule comprising the crystal (W = 1). According to the Boltzmann equation, the entropy of this system is zero.
02:16First Law of Thermodynamics
Energy Conservation
00:37First Law of Thermodynamics
The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed. This can be demonstrated within a classic food web where light energy from the sun is harnessed as radiant energy by plants, converted into chemical energy, and stored as complex carbohydrates. The vegetation is then consumed by animals and during the digestion process, the sugars release energy as heat. The sugars also produce chemical energy that either gets used up doing work, stored in...