Related Experiment Video
Updated: Jul 4, 2026
11:11
Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation
Published on: May 2, 2016
Spin based heat engine: demonstration of multiple rounds of algorithmic cooling
1Institute for Quantum Computing and Department of Physics, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
Physical Review Letters
|June 4, 2008
Summary
Researchers used heat-bath algorithmic cooling to purify a single qubit, exceeding the Shannon bound. This quantum information processing technique achieves nearly pure qubits by combining control and environmental interaction.
Area of Science:
- Quantum Information Science
- Quantum Computing
- Solid-State NMR
Background:
- Quantum systems require high fidelity for reliable information processing.
- Algorithmic cooling is a method to improve qubit polarization beyond equilibrium limits.
Purpose of the Study:
- To experimentally demonstrate multiple rounds of heat-bath algorithmic cooling.
- To purify a single qubit beyond the Shannon bound using a 3-qubit system.
Main Methods:
- Utilized a 3-qubit solid-state nuclear magnetic resonance (NMR) quantum information processor.
- Implemented a cooling algorithm involving entropy pumping into a heat bath.
- Combined high-fidelity coherent control with controlled environmental interaction.
Main Results:
- Achieved qubit purification 1.69 times the heat-bath polarization, surpassing the closed-system Shannon bound.
- Demonstrated successful multiple rounds of algorithmic cooling.
- Showcased the effectiveness of combining coherent control and environmental coupling.
Conclusions:
- Heat-bath algorithmic cooling can significantly enhance qubit purity.
- This technique offers a pathway to achieving nearly pure qubits in quantum processors.
- The demonstrated level of quantum control is promising for future quantum information applications.
Related Concept Videos
01:20Mechanisms of Heat Transfer II
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
01:14Mechanisms of Heat Transfer I
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
01:10Heat Engines
A heat engine is a device used to extract heat from a source and then convert it into mechanical work used for various applications. For example, a steam engine on an old-style train can produce the work needed for driving the train.
Whenever we consider heat engines (and associated devices such as refrigerators and heat pumps), we do not use the standard sign convention for heat and work. For convenience, we assume that the symbols Qh, Qc, and W represent only the amounts of heat transferred...
Whenever we consider heat engines (and associated devices such as refrigerators and heat pumps), we do not use the standard sign convention for heat and work. For convenience, we assume that the symbols Qh, Qc, and W represent only the amounts of heat transferred...
01:14Mechanisms of Heat Transfer
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant heat.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant heat.
01:19Mechanism of heat transfer
Understanding heat transfer mechanisms is essential for understanding how our bodies maintain balance in different environmental conditions. When the environment is thermoneutral, the body is in a state of balance, neither using nor releasing energy to maintain its core temperature. However, when the environment is not thermoneutral, the body employs four heat transfer mechanisms to maintain homeostasis: conduction, convection, evaporation, and radiation. These mechanisms facilitate heat...
01:30The Carnot Cycle
Converting work to heat is an irreversible process, and the purpose of a heat engine is to reverse the effect partially. Heat engines aim to increase the efficiency of the reversal, that is, maximize the work retrieved from heat. If the efficiency of a heat engine were 100%, it would imply reversing the process completely without introducing any other effect. Thus, it would violate the second law of thermodynamics.
What could be the theoretical limit to the efficiency of a heat engine? The...
What could be the theoretical limit to the efficiency of a heat engine? The...