Related Experiment Video
Updated: May 21, 2026
12:19
Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source
Published on: April 4, 2017
Quantum interference between two single photons of different microwave frequencies
François Nguyen1, Eva Zakka-Bajjani, Raymond W Simmonds
1National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA. francois.nguyen@colorado.edu
Physical Review Letters
|June 12, 2012
Summary
Researchers achieved quantum interference between two single microwave photons using a superconducting resonator. This demonstrates high-fidelity two-photon entanglement, a key step for quantum computing and communication.
Area of Science:
- Quantum optics
- Superconducting circuits
- Quantum information science
Background:
- Quantum interference is a fundamental phenomenon in quantum mechanics.
- Entanglement of microwave photons is crucial for developing quantum networks and processors.
- Superconducting circuits offer a promising platform for scalable quantum technologies.
Purpose of the Study:
- To measure quantum interference between two single microwave photons.
- To demonstrate high-fidelity two-photon entanglement using superconducting circuits.
- To explore parametric frequency conversion for photon manipulation.
Main Methods:
- Trapping single microwave photons in a superconducting resonator.
- Utilizing parametric frequency conversion via a superconducting quantum interference device (SQUID).
- Mixing mode currents of two cavity harmonics for frequency conversion.
Main Results:
- Successful measurement of quantum interference between two single microwave photons.
- Demonstration of a two-photon entanglement operation with high fidelity.
- Initial frequencies of the photons were approximately 6 GHz apart.
Conclusions:
- Parametric frequency conversion in superconducting resonators enables robust quantum interference.
- High-fidelity two-photon entanglement is achievable, paving the way for advanced quantum applications.
- This work advances the control and manipulation of microwave photons for quantum technologies.
Related Concept Videos
02:18Interference and Diffraction
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.
01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
01:07Interference and Superposition of Waves
When two waves of the same nature occur in the same region simultaneously, they result in interference. Interference of waves implies that the net effect of the waves is the sum of the individual waves' effects. However, it does not imply that the individual waves affect the propagation of other waves.
Interference occurs in mechanical waves, such as sound waves, waves on a string, and surface water waves. Mechanical waves correspond to the physical displacement of particles. Hence,...
Interference occurs in mechanical waves, such as sound waves, waves on a string, and surface water waves. Mechanical waves correspond to the physical displacement of particles. Hence,...
01:10Interference: Path Lengths
Consider two sources of sound, that may or may not be in phase, emitting waves at a single frequency, and consider the frequencies to be the same.
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
01:13¹H NMR Signal Multiplicity: Splitting Patterns
When protons A and X are coupled, their nuclear spin energy levels are slightly modified. This is because the energy required to excite proton A to a spin state parallel to proton X is slightly different from the energy required for it to become anti-parallel to spin X. Consequently, there are two possible excitation frequencies for A (A1 and A2), depending on the spin state of X, and vice versa. The mutual nature of coupling implies that the difference between frequencies A1 and A2, indicated...
01:14Molecular Spectroscopy: Absorption and Emission
Molecules possess discrete energy levels called quantum states. Unlike atoms, which have simpler energy levels, molecules possess additional rotational and vibrational energy levels. Each energy level is separated by an energy gap, with the gaps between adjacent electronic, vibrational, and rotational levels varying significantly. The three types of energy levels in a diatomic molecule are shown in Figure 1.