Related Experiment Video
Updated: Jul 31, 2025
09:23
Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
Published on: May 30, 2014
14.6K
Dynamics-Based Entanglement Witnesses for Non-Gaussian States of Harmonic Oscillators
Pooja Jayachandran1, Lin Htoo Zaw1, Valerio Scarani1,2
1Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543.
Physical Review Letters
|May 8, 2023
Summary
We developed a new method to detect quantum entanglement in continuous variable systems using harmonic oscillator dynamics. This approach is robust against classical explanations and identifies non-Gaussian states missed by other techniques.
Area of Science:
- Quantum physics
- Quantum information science
Background:
- Entanglement is a key quantum resource.
- Detecting entanglement in continuous variable systems is challenging.
- Existing methods may miss certain non-Gaussian states.
Purpose of the Study:
- Introduce a novel entanglement witness for continuous variable systems.
- Develop a method robust against classical theories.
- Identify non-Gaussian states missed by other criteria.
Main Methods:
- Utilize the dynamics of coupled harmonic oscillators.
- Apply the Tsirelson nonclassicality test on one normal mode.
- Measure only the sign of a coordinate at specific times.
Main Results:
- The dynamic-based witness infers entanglement without full state knowledge.
- The method is analogous to a Bell inequality, avoiding false positives.
- Successfully detects non-Gaussian states missed by other witnesses.
Conclusions:
- The proposed entanglement witness is a powerful tool for continuous variable systems.
- This method offers a robust and efficient way to identify quantum entanglement.
- Advances the detection of non-Gaussian quantum states.
Related Concept Videos
01:04Oscillations about an Equilibrium Position
5.5K
Stability is an important concept in oscillation. If an equilibrium point is stable, a slight disturbance of an object that is initially at the stable equilibrium point will cause the object to oscillate around that point. For an unstable equilibrium point, if the object is disturbed slightly, it will not return to the equilibrium point. There are three conditions for equilibrium points—stable, unstable, and half-stable. A half-stable equilibrium point is also unstable, but is named so...
5.5K
02:32The de Broglie Wavelength
26.0K
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...
26.0K
01:06Forced Oscillations
6.6K
When an oscillator is forced with a periodic driving force, the motion may seem chaotic. The motions of such oscillators are known as transients. After the transients die out, the oscillator reaches a steady state, where the motion is periodic, and the displacement is determined.
6.6K
01:07Damped Oscillations
5.8K
In the real world, oscillations seldom follow true simple harmonic motion. A system that continues its motion indefinitely without losing its amplitude is termed undamped. However, friction of some sort usually dampens the motion, so it fades away or needs more force to continue. For example, a guitar string stops oscillating a few seconds after being plucked. Similarly, one must continually push a swing to keep a child swinging on a playground.
Although friction and other non-conservative...
Although friction and other non-conservative...
5.8K
01:23Stability of Equilibrium Configuration
490
Understanding the stability of equilibrium configurations is a fundamental part of mechanical engineering. In any system, there are three distinct types of equilibrium: stable, neutral, and unstable.
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
490
01:23Energy in Simple Harmonic Motion
9.1K
To determine the energy of a simple harmonic oscillator, consider all the forms of energy it can have during its simple harmonic motion. According to Hooke's Law, the energy stored during the compression/stretching of a string in a simple harmonic oscillator is potential energy. As the simple harmonic oscillator has no dissipative forces, it also possesses kinetic energy. In the presence of conservative forces, both energies can interconvert during oscillation, but the total energy remains...
9.1K