Related Experiment Video
Updated: May 28, 2026
07:56
A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Measurement-induced chaos with entangled states
1Research Institute for Solid State Physics and Optics, H-1525 Budapest Post Office Box 49, Hungary.
Physical Review Letters
|October 11, 2011
Summary
Investigating two-qubit systems undergoing entanglement purification reveals sensitivity to initial states. Asymptotic limits show fractal boundaries between separable and entangled states, with noise introducing new stable dynamics.
Area of Science:
- Quantum Information Science
- Quantum Computing
- Many-Body Quantum Systems
Background:
- Entanglement is a key resource in quantum information processing.
- Entanglement purification protocols are essential for combating noise and decoherence.
- Understanding the dynamics of multi-qubit systems is crucial for scalable quantum technologies.
Purpose of the Study:
- To investigate the dynamics of two-qubit systems under iterative entanglement purification.
- To analyze the sensitivity of these dynamics to initial conditions.
- To characterize the asymptotic states and the influence of noise.
Main Methods:
- Simulation of an ensemble of identically prepared two-qubit systems.
- Application of iterative measurements and conditional selection within an entanglement purification protocol.
- Analysis of system dynamics and asymptotic behavior.
Main Results:
- The dynamics exhibit strong sensitivity to initial conditions.
- Two distinct asymptotic states (separable and fully entangled) are identified, with fractal boundaries.
- Incoherent noise introduces an additional stable asymptotic cycle.
Conclusions:
- Entanglement purification dynamics are highly sensitive to initial states, leading to complex asymptotic behaviors.
- Fractal structures emerge at the boundaries of separable and entangled states.
- Noise significantly alters the long-term dynamics, creating new stable attractors.
Related Concept Videos
02:39Entropy
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...
01:18Entropy
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...
01:14The Entropy as a State Function
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...
01:10Entropy Change in Reversible Processes
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.
04:08The Uncertainty Principle
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 mathematically...
01:21Entropy Changes Accompanying Specific Processes
Entropy, a measure of disorder in a system, changes during phase transitions like freezing or boiling. At the transition temperature Ttrs, where two phases are in equilibrium, the phase transition is a reversible process. The entropy change can be calculated from a substance's enthalpy of transition using the equation ΔStrs = ΔtrsH /Ttrs.When a perfect gas expands isothermally from one volume to another, entropy increases logarithmically with volume. Conversely, isothermal compression results...