B. Roy Frieden
Encyclopedia
B. Roy Frieden is an American
mathematical physicist.
Frieden obtained a Ph.D. in Optics
from The Institute of Optics
at the University of Rochester
. His doctoral thesis advisor was Robert E. Hopkins
. Frieden is now an Emeritus Professor of Optical Sciences
at the University of Arizona
.
Frieden is best known for his extensive work on Fisher information
as a grounding principle for deriving and elaborating physical theory. (Examples are the Schrödinger wave equation of quantum mechanics
, and the Maxwell-Boltzmann distribution of statistical mechanics
.) Such theories take the form of differential equations or probability distribution
functions.
Central to Frieden's derivations is the mathematical variational principle
of extreme physical information
(EPI). This principle builds on the well-known idea that the observation of a "source" phenomenon is never completely accurate. That is, information is inevitably lost in transit from source to observation. Furthermore, the random errors that creep in are presumed to define the distribution function of the source phenomenon. As Frieden puts it, "the physics lies in the fluctuations." Finally, the information loss may be shown to be an extreme value. Thus if the observed level of Fisher information in the data has value I, and the level of Fisher information that existed at the source has value J, the EPI principle states that I − J = extremum. In most situations, the extremum is a minimum, meaning that there is a tendency for any observation to faithfully match up with its source.
Frieden has used Fisher information and the EPI principle to derive most existing fundamental laws of physics
, and some new and existing laws of biology
, cancer
growth, chemistry
, and economics
. Frieden argues that Fisher information, especially its loss I − J during observation, and EPI make up a general method for deriving scientific laws.
Several reviewers doubt the physical and mathematical correctness of Frieden's ideas; see, for example, Raymond F. Streater's Lost Causes in Theoretical Physics: Physics from Fisher Information, and Cosma Shalizi's review of Physics from Fisher Information.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
mathematical physicist.
Frieden obtained a Ph.D. in Optics
Optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
from The Institute of Optics
The Institute of Optics
The Institute of Optics is a department and research center at the University of Rochester in Rochester, New York. The Institute grants degrees at the bachelors, masters and doctoral levels through the University of Rochester School of Engineering and Applied Sciences...
at the University of Rochester
University of Rochester
The University of Rochester is a private, nonsectarian, research university in Rochester, New York, United States. The university grants undergraduate and graduate degrees, including doctoral and professional degrees. The university has six schools and various interdisciplinary programs.The...
. His doctoral thesis advisor was Robert E. Hopkins
Robert E. Hopkins
Robert E. Hopkins was president of the Optical Society of America in 1973.Recognized as an expert in optical instrument design, aspheric optics, interferometry, lasers, and lens testing, Hopkins has been characterized as the “father of optical engineering.”Born in Belmont, MA, in 1915, Hopkins...
. Frieden is now an Emeritus Professor of Optical Sciences
Optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
at the University of Arizona
University of Arizona
The University of Arizona is a land-grant and space-grant public institution of higher education and research located in Tucson, Arizona, United States. The University of Arizona was the first university in the state of Arizona, founded in 1885...
.
Frieden is best known for his extensive work on Fisher information
Fisher information
In mathematical statistics and information theory, the Fisher information is the variance of the score. In Bayesian statistics, the asymptotic distribution of the posterior mode depends on the Fisher information and not on the prior...
as a grounding principle for deriving and elaborating physical theory. (Examples are the Schrödinger wave equation of quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
, and the Maxwell-Boltzmann distribution of statistical mechanics
Statistical mechanics
Statistical mechanics or statistical thermodynamicsThe terms statistical mechanics and statistical thermodynamics are used interchangeably...
.) Such theories take the form of differential equations or probability distribution
Probability distribution
In probability theory, a probability mass, probability density, or probability distribution is a function that describes the probability of a random variable taking certain values....
functions.
Central to Frieden's derivations is the mathematical variational principle
Variational principle
A variational principle is a scientific principle used within the calculus of variations, which develops general methods for finding functions which minimize or maximize the value of quantities that depend upon those functions...
of extreme physical information
Extreme physical information
Extreme physical information is a principle, first described and formulated in 1998 by B. Roy Frieden, Emeritus Professor of Optical Sciences at the University of Arizona, that states, the precipitation of scientific laws can be derived through Fisher information, taking the form of differential...
(EPI). This principle builds on the well-known idea that the observation of a "source" phenomenon is never completely accurate. That is, information is inevitably lost in transit from source to observation. Furthermore, the random errors that creep in are presumed to define the distribution function of the source phenomenon. As Frieden puts it, "the physics lies in the fluctuations." Finally, the information loss may be shown to be an extreme value. Thus if the observed level of Fisher information in the data has value I, and the level of Fisher information that existed at the source has value J, the EPI principle states that I − J = extremum. In most situations, the extremum is a minimum, meaning that there is a tendency for any observation to faithfully match up with its source.
Frieden has used Fisher information and the EPI principle to derive most existing fundamental laws of physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, and some new and existing laws of biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
, cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
growth, chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, and economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...
. Frieden argues that Fisher information, especially its loss I − J during observation, and EPI make up a general method for deriving scientific laws.
Several reviewers doubt the physical and mathematical correctness of Frieden's ideas; see, for example, Raymond F. Streater's Lost Causes in Theoretical Physics: Physics from Fisher Information, and Cosma Shalizi's review of Physics from Fisher Information.
External links
- Roy Frieden Professor Emeritus of Optical Sciences.
- Frieden, B. Roy, "Fisher Information, a New Paradigm for Science: Introduction, Uncertainty principles, Wave equations, Ideas of Escher, Kant, Plato and Wheeler." This essay is continually revised.
- Any old maths: Roy Frieden's project to unify physics based on Fisher information from New ScientistNew ScientistNew Scientist is a weekly non-peer-reviewed English-language international science magazine, which since 1996 has also run a website, covering recent developments in science and technology for a general audience. Founded in 1956, it is published by Reed Business Information Ltd, a subsidiary of...
issue 2174, 20 February 1999, p. 53