Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)01:20

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
Hybridization of Atomic Orbitals II03:35

Hybridization of Atomic Orbitals II

sp3d and sp3d 2 Hybridization
¹H NMR: Long-Range Coupling01:27

¹H NMR: Long-Range Coupling

The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.
Hybridization of Atomic Orbitals I03:24

Hybridization of Atomic Orbitals I

The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)01:22

Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)

Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
Energy Stored In A Coaxial Cable01:31

Energy Stored In A Coaxial Cable

A coaxial cable consists of a central copper conductor used for transmitting signals, followed by an insulator shield, a metallic braided mesh that prevents signal interference, and a plastic layer that encases the entire assembly.
In the simplest form, a coaxial cable can be represented by two long hollow concentric cylinders in which the current flows in opposite directions. The magnetic field inside and outside the coaxial cable is determined by using Ampère's law. The magnetic field inside...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Coupling of single nanodiamonds hosting SiV color centers to plasmonic double bowtie microantennas.

Nanotechnology·2025
Same author

Study of the influence of alcohol on the photostability of four UV filters.

European review for medical and pharmacological sciences·2021
Same author

Soap and syndets: differences and analogies, sources of great confusion.

European review for medical and pharmacological sciences·2020
Same author

Influence of Cosmetic Type and Distribution Channel on the Presence of Regulated Fragrance Allergens: Study of 2044 Commercial Products.

Clinical reviews in allergy & immunology·2020
Same author

Mitigating the photocurrent persistence of single ZnO nanowires for low noise photodetection applications.

Nanotechnology·2018
Same author

Study of the influence of substrate and spectrophotometer characteristics on the in vitro measurement of sunscreens efficiency.

European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences·2018

Related Experiment Video

Updated: Jun 29, 2026

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
07:56

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

Published on: September 5, 2019

Entangled quantum key distribution over two free-space optical links.

C Erven1, C Couteau, R Laflamme

  • 1Department of Physics and Astronomy, Institute for Quantum Computing, University ofWaterloo, Waterloo, ON, Canada. cerven@iqc.ca

Optics Express
|October 15, 2008
PubMed
Summary

This study demonstrates the first real-time quantum key distribution (QKD) system using entangled photons over free-space links. The secure key generation rate reached 85 bits/s, showcasing practical QKD implementation.

More Related Videos

Quasi-light Storage for Optical Data Packets
07:45

Quasi-light Storage for Optical Data Packets

Published on: February 6, 2014

Generation and Coherent Control of Pulsed Quantum Frequency Combs
06:42

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

Related Experiment Videos

Last Updated: Jun 29, 2026

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
07:56

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

Published on: September 5, 2019

Quasi-light Storage for Optical Data Packets
07:45

Quasi-light Storage for Optical Data Packets

Published on: February 6, 2014

Generation and Coherent Control of Pulsed Quantum Frequency Combs
06:42

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

Area of Science:

  • Quantum Information Science
  • Quantum Cryptography
  • Free-Space Optics

Background:

  • Quantum Key Distribution (QKD) offers provably secure communication.
  • Implementing QKD over free-space optical links presents challenges in maintaining entanglement and synchronization over distance.
  • Previous QKD systems have often relied on fiber optic cables or shorter free-space distances.

Purpose of the Study:

  • To demonstrate the first real-time implementation of a quantum key distribution (QKD) system utilizing entangled photon pairs.
  • To establish secure communication over two distinct free-space optical telescope links.
  • To assess the performance of the QKD system in terms of key generation rate and error rates.

Main Methods:

  • Generation of entangled photon pairs using type-II spontaneous parametric down-conversion.
  • Transmission of entangled photons over two free-space optical links with lengths of 435 m and 1,325 m, totaling 1,575 m separation.
  • Utilization of passive polarization analysis, GPS timing receivers for synchronization, and custom software for protocol execution, including error correction and privacy amplification.

Main Results:

  • Successful real-time operation of the QKD system over 6.5 hours during nighttime.
  • Observed an average raw key generation rate of 565 bits/s.
  • Achieved an average quantum bit error rate (QBER) of 4.92% and an average secure key generation rate of 85 bits/s.

Conclusions:

  • The successful implementation validates the feasibility of real-time QKD using entangled photons over significant free-space distances.
  • The system's performance metrics demonstrate its potential for practical secure communication applications.
  • This work paves the way for future advancements in long-distance, free-space quantum communication networks.