Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Uncertainty in Measurement: Accuracy and Precision

Uncertainty in Measurement: Accuracy and Precision

Scientists typically make repeated measurements of a quantity to ensure the quality of their findings and to evaluate both the precision and the accuracy of their results. Measurements are said to be precise if they yield very similar results when repeated in the same manner. A measurement is considered accurate if it yields a result that is very close to the true or the accepted value. Precise values agree with each other; accurate values agree with a true value.

Uncertainty in Measurement: Reading Instruments

Uncertainty in Measurement: Reading Instruments

Counting is the type of measurement that is free from uncertainty, provided the number of objects being counted does not change during the process. Such measurements result in exact numbers. By counting the eggs in a carton, for instance, one can determine exactly how many eggs are there in the carton. Similarly, the numbers of defined quantities are also exact. For example, 1 foot is exactly 12 inches, 1 inch is exactly 2.54 centimeters, and 1 gram is exactly 0.001 kilograms. Quantities...

You might also read

Related Articles

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

Sort by

Same author

Case of Sudden Death Seven Hours after Delivery-Air Found in the Heart.

Medical examiner (Philadelphia, Pa.)·2023

Same author

Meningococcemia.

Archives of pediatrics·2010

Same author

Comment on berry and hachinski

Archives of neurology·2000

Same author

Idiopathic Cardiomyopathy.

Current treatment options in cardiovascular medicine·2000

Same author

A reconsideration of Wattieza Stockmans (here attributed to Cladoxylopsida) based on a new species from the Devonian of Venezuela.

Review of palaeobotany and palynology·2000

Same author

Discrete periodic melting point observations for nanostructure ensembles

Physical review letters·2000

Search research articles

Related Experiment Video

Updated: Jul 27, 2026

Implementation of a Reference Interferometer for Nanodetection

Implementation of a Reference Interferometer for Nanodetection

Published on: April 26, 2014

Optimal states and almost optimal adaptive measurements for quantum interferometry

Berry¹, Wiseman

¹Department of Physics, The University of Queensland, St. Lucia 4072, Australia.

Physical Review Letters

|December 2, 2000

Summary

Researchers identified the best N-photon input state for interferometers, achieving a phase difference variance of approximately pi(2)/N2. An adaptive measurement scheme closely matches this optimal precision, improving upon previous methods.

More Related Videos

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Published on: May 30, 2014

Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

Published on: April 4, 2017

Related Experiment Videos

Last Updated: Jul 27, 2026

Implementation of a Reference Interferometer for Nanodetection

Implementation of a Reference Interferometer for Nanodetection

Published on: April 26, 2014

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Published on: May 30, 2014

Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source

Published on: April 4, 2017

Area of Science:

Quantum optics
Interferometry
Quantum metrology

Background:

Interferometers are crucial for precise measurements.
Estimating phase differences is key to interferometer performance.
Previous studies explored N-photon states with suboptimal phase sensitivity.

Purpose of the Study:

Derive the optimal N-photon two-mode input state for phase estimation.
Achieve a phase sensitivity scaling as O(N^-2).
Develop a practical measurement scheme for optimal phase estimation.

Main Methods:

Theoretical derivation of the optimal N-photon two-mode input state.
Analysis of phase measurement variance for the optimal state.
Introduction and analysis of an adaptive measurement scheme.

Main Results:

The optimal N-photon state yields a phase variance of approximately pi(2)/N^2.
This represents a significant improvement over previous O(N^-1) or O(N^-1/2) sensitivities.
An adaptive measurement scheme closely approximates optimal precision.

Conclusions:

The derived N-photon state offers superior phase sensitivity in interferometry.
Adaptive measurement schemes can realize near-optimal phase estimation.
This work advances quantum metrology for enhanced precision measurements.