Related Experiment Video
Updated: Jan 4, 2026
09:10
Fabrication and Testing of Microfluidic Optomechanical Oscillators
Published on: May 29, 2014
12.6K
Observing and Verifying the Quantum Trajectory of a Mechanical Resonator
Massimiliano Rossi1,2, David Mason1,2, Junxin Chen1,2
1Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
Physical Review Letters
|November 9, 2019
Summary
Researchers tracked the quantum state of a mechanical resonator using continuous optical measurement. This method achieved high-purity coherent states, paving the way for quantum state creation and testing decoherence models.
Area of Science:
- Quantum mechanics
- Quantum optics
- Macroscopic quantum phenomena
Background:
- Continuous weak measurement enables tracking quantum systems over time.
- Previous work demonstrated quantum trajectory recording for photons and qubits.
Purpose of the Study:
- To apply continuous weak measurement to a macroscopic mechanical resonator.
- To follow the quantum trajectory of the resonator's motional state.
- To create advanced quantum states and test decoherence models.
Main Methods:
- Continuous optical measurement of a macroscopic mechanical resonator.
- Real-time recording of the resonator's quantum trajectory.
- Retrodictive measurement protocol for state purity verification.
Main Results:
- Successfully followed the quantum trajectory of the resonator's motional state.
- Achieved coherent states with 78% purity, comparable to a displaced thermal state (0.14 occupation).
- Observed quantum state collapse and decoherence during measurement.
Conclusions:
- Continuous weak measurement is effective for macroscopic quantum systems.
- This technique allows for measurement-based creation of quantum states.
- The study provides a platform for testing fundamental physics, including gravitational decoherence.
Related Concept Videos
01:09Torsional Pendulum
7.0K
A torsional pendulum involves the oscillation of a rigid body in which the restoring force is provided by the torsion in the string from which the rigid body is suspended. Ideally, the string should be massless; practically, its mass is much smaller than the rigid body's mass and is neglected.
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played...
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played...
7.0K
02:32The de Broglie Wavelength
32.8K
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...
32.8K
01:06Physical Pendulum
2.6K
When a rigid body is hanging freely from a fixed pivot point and is displaced, it oscillates similar to a simple pendulum and is known as a physical pendulum. The period and angular frequency of a physical pendulum are obtained by using the small-angle approximation and drawing parallels with a spring-mass system. The small-angle approximation (sinθ=θ) is valid up to about 14°.
When dealing with complicated systems, the mass moment of inertia is an important parameter, as it...
When dealing with complicated systems, the mass moment of inertia is an important parameter, as it...
2.6K
01:19Concept of Resonance and its Characteristics
6.0K
If a driven oscillator needs to resonate at a specific frequency, then very light damping is required. An example of light damping includes playing piano strings and many other musical instruments. Conversely, to achieve small-amplitude oscillations as in a car's suspension system, heavy damping is required. Heavy damping reduces the amplitude, but the tradeoff is that the system responds at more frequencies. Speed bumps and gravel roads prove that even a car's suspension system is not...
6.0K
01:14Sound Waves: Resonance
3.1K
Resonance is produced depending on the boundary conditions imposed on a wave. Resonance can be produced in a string under tension with symmetrical boundary conditions (i.e., has a node at each end). A node is defined as a fixed point where the string does not move. The symmetrical boundary conditions result in some frequencies resonating and producing standing waves, while other frequencies interfere destructively. Sound waves can resonate in a hollow tube, and the frequencies of the sound...
3.1K
01:04Oscillations about an Equilibrium Position
6.5K
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...
6.5K