Category: Physics

Philosophical Implications of Quantum Mechanics

Richard Feynman (1918-1988) argues in his famous Lectures on Physics (1961/62) that finite accuracy of measurement also makes the future very unpredictable, because even very small errors in prediction have cascading effects that lead to vastly different outcomes. Thus, the difference between a classical interpretation (deterministic) and a quantum-mechanical explanation (indeterminisitc) is not as categorical as we sometimes assume. He compares classical and quantum-mechanical approaches to physics, and comes to the conclusion that “…it  is not true that we can pursue science completely by using only those concepts which are directly subject to experiment.” If this applies to physics, it is...

Richard Feynman (1918-1988)

Richard Feynman is a physicist who won the Nobel Prize,  worked on the Manhattan Project, he played a key role in explaining the Space Shuttle Challenger disaster, and he is known for the “Feynman diagrams” that symbolize particle collisions. He gave famous introductory lectures on physics, which is now available online. The online edition features all the lectures on matter, electromagnetism, and quantum mechanics. It’s not easy to understand, but as Feynman himself once said, “Hell, if I could explain it to the average person, it wouldn’t have been worth the Nobel Prize.“ In 1959, he gave a lecture that...

David Bohm (1917-1992)

David Joseph Bohm lived from 20 December 1917 to 27 October 1992. He was an American theoretical physicist who contributed innovative and unorthodox ideas to quantum theory, philosophy of mind, and neuro-psychology. He is considered to be one of the most significant theoretical physicists of the 20th century. He was a good friend of Einstein. Biography David Bohm was born in Wilkes-Barre, Pennsylvania to Jewish parents. His father owned a local furniture store. Bohm graduated from Pennsylvania State College in 1939. After attending the California Institute of Technology in 1940, he acquired a doctorate in theoretical physics at the University...

Reductionism or Emergence?

Here are some quotes about the controversy between reductionism and emergence as basic paradigm for physics. Robert Laughlin: A Different Universe: Reinventing Physics from the Bottom Down. 2005. From the Introduction: “Much as I dislike the idea of ages, I think a good case can be made that science has now moved from an Age of Reductionism to an Age of Emergence, a time when the search for ultimate causes of things shifts from the behavior of parts to the behavior of the collective. It is difficult to identify a specific moment when this transition occurred because it was gradual and...

A. M. Turing: Computing Machinery and Intelligence. 1950

Source: Mind 49: 433-460. 1. The Imitation Game I propose to consider the question, “Can machines think?” This should begin with definitions of the meaning of the terms “machine” and “think.” The definitions might be framed so as to reflect so far as possible the normal use of the words, but this attitude is dangerous, If the meaning of the words “machine” and “think” are to be found by examining how they are commonly used it is difficult to escape the conclusion that the meaning and the answer to the question, “Can machines think?” is to be sought in a...

Henri Poincaré: The Relativity of Space. 1897

Source: This is a chapter from Science & Method (1897). Even today, it’s an interesting book to read. I. IT is impossible to picture empty space. All our efforts to imagine pure space from which the changing images of material objects are excluded can only result in a representation in which highly-coloured surfaces, for instance, are replaced by lines of slight colouration, and if we continued in this direction to the end, everything would disappear and end in nothing. Hence arises the irreducible relativity of space. Whoever speaks of absolute space uses a word devoid of meaning. This is a...

Radical Abundance through Nanotechnology?

In his newest book, Radical Abundance: How a Revolution in Nanotechnology Will Change Civilization, 2013, he tells the history of nanotechnology from its beginnings to today, and then he turns towards the future: What can we expect from the accelerating breakthroughs generated by nano-technological research? Will it benefit humanity, or cause us harm? He is very optimistic, and his answer is given in the title: We are going to experience radical abundance based on these technological breakthroughs.

Scales of the Universe: Small, Large, and Complex

It is difficult for us to fathom the scale of the universe. The differences between the smallest structures and the largest are so enormous that linear scales are useless. We need exponential scales, which make the numbers appear to be easy, even when the geometry is simply incomprehensible. A simple example can demonstrate these size differences – there are more atoms in a glass of water than there are glasses of water in all the oceans combined. (If you don’t believe it, here is the math.)

On an exponential scale in meters, humans are located at the midpoint between the nanometer scale (1×10−9 m) (a strand of DNA is 3 nanometers thick) and the scale of stars ( the sun is 1.4 ×109 m in diameter.) Reaching “down”, what we try to do in nanotechnology, is just as difficult as reaching “up,” exploring the solar system with our probes. But, the journey is only beginning.

Emergence

We are currently experiencing a paradigm shift in scientific thinking and explanation, away from reductionist and constructivist approaches. This shift is the result of the introduction of computers and the internet. Scientific researchers are now capable of collecting and processing much more information than ever before, and advanced modeling techniques allow them to develop and test scientific theories in ways that were simply not possible 20 or even 10 years ago. Traditionally, physics operated with a reductionist approach: it breaks down complex phenomena into simpler parts that can be studied independently. Once the basic laws were understood, scientists thought they...

Isaac Newton

He is one of the most important physicists and mathematicians of all time. Biography This short biography is quoted from the BBC History site. Isaac Newton was born on 4 January 1643 in Woolsthorpe, Lincolnshire. His father was a prosperous farmer, who died three months before Newton was born. His mother remarried and Newton was left in the care of his grandparents. In 1661, he went to Cambridge University where he became interested in mathematics, optics, physics and astronomy. In October 1665, a plague epidemic forced the university to close and Newton returned to Woolsthorpe. The two years he spent...

Higgs Boson – How Particles Acquire Mass

In response to a 1993 challenge from the UK Science Minister to produce a one-page simple explanation of the Higgs boson, the following entries were submitted.  (Quoted from “Physics World”, Volume 6 Number 9). As we all know, the Higgs has been found in July 2012 by the Large Hadron Collider. 1. How Particles Acquire Mass By Mary and Ian Butterworth, Imperial College London, and Doris and Vigdor Teplitz, Southern Methodist University, Dallas, Texas, USA. Matter is made of molecules; molecules of atoms; atoms of a cloud of electrons about one-hundred-millionth of a centimeter and a nucleus about one-hundred-thousandth the...

Discoveries leading to the Standard Model

The following timeline of discoveries the led to the Standard Model is quoted from Fermilab’s website. “The current theoretical framework that describes elementary particles and their forces, known as the Standard Model, is based on experiments that started in 1897 with the discovery of the electron. Today, we know that there are six leptons, six quarks and four force carriers. The list below gives the dates of important discoveries, the names of scientists and laboratories involved, and Nobel Prizes awarded for the discoveries. Quarks: up (u) down (d) 1964 Gell-Mann and, independently, Zweig introduce the idea of quarks, the building...

Schrödinger’s Cat

In 1935 Schrodinger published an essay describing the conceptual problems in Quantum mechanics. A brief paragraph in this essay described the cat paradox: “One can even set up quite ridiculous cases. A cat is penned up in a steel chamber, along with the following diabolical device (which must be secured against direct interference by the cat): in a Geiger counter there is a tiny bit of radioactive substance, so small that perhaps in the course of one hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a...

Quantum Nonlocality

Quantum nonlocality is a paradox that was described first by Einstein, Podolsky, and Rosen (EPR), who published the idea in 1935. The EPR paradox draws attention to a phenomenon predicted by quantum mechanics known as quantum entanglement, in which measurements on spatially separated quantum systems can instantaneously influence one another. As a result, quantum mechanics violates a principle formulated by Einstein, known as the principle of locality or local realism, which states that changes performed on one physical system should have no immediate effect on another spatially separated system. Our “local realistic” view of the world assumes that phenomena are...

Vacuum Fluctuations

How the Universe can come from Nothing: The following quotes address vacuum fluctuations and the idea that things – perhaps even the entire universe – can indeed arise from nothing via natural processes. Vacuum Fluctuations and Virtual Particles In the everyday world, energy is always unalterably fixed; the law of energy conservation is a cornerstone of classical physics. But in the quantum microworld, energy can appear and disappear out of nowhere in a spontaneous and unpredictable fashion. (Davies, 1983, 162) The uncertainty principle implies that particles can come into existence for short periods of time even when there is not...

Albert Einstein

Quoted from the  Albert Einstein Website, created by  Hans-Josef Küpper: “Albert Einstein was born on March 14, 1879 in Ulm, the first child of the Jewish couple Hermann and Pauline Einstein, née Koch. In June 1880 the family moved to Munich where Hermann Einstein and his brother Jakob founded the electrical engineering company Einstein & Cie. Albert Einstein’s sister Maria, called Maja, was born on November 18, 1881. Einstein’s childhood was a normal one, except that to his family’s irritation, he learnt to speak at a late age. Beginning in 1884 he received private education in order to get prepared...

Standard Model

The picture to the left can be found in Wikipedia’s article about the Standard Model. The Elementary Particles of Matter Physicists have found 12 building blocks that are the fundamental constituents of matter. (The first three columns in the chart.) Our world is made of just three of these building blocks: the up quark, the down quark and the electron, in the first column.  That’s enough to make protons and neutrons and to form atoms and molecules. The electron neutrino, (an electron without electrical charge) observed in the decay of other particles, completes the first set of four building blocks....

What is Quantum Mechanics?

Quantum mechanics is a branch of physics; it was developed between 1900 and 1930, and  it explains the behavior of sub-atomic particles, atoms, molecules and nuclei. Attempts to combine it with the general and special theory of relativity leads to new and revolutionary types of theories. Experimental evidence forced the creation of new concepts, like the particle properties of radiation, the wave properties of matter, the quantization of physical properties, or  the idea that one can no longer know exactly where a single particle such as an electron is at any one moment. Some of the basic insights of quantum...

Physicists

Physicists study physical phenomena scientifically. These phenomena span all length scales: from sub-atomic particles of which all ordinary matter is made (particle physics) to the behavior of the material Universe as a whole (cosmology).

Physics Quotes

Stephen Hawking’s explanation of the creation of matter and energy: “Where did they [i.e., 1080particles in the universe] all come from? The answer is that, in quantum theory, particles can be created out of energy in the form of particle/antiparticle pairs. But that just raises the question of where the energy came from. The answer is that the total energy of the universe is exactly zero. The matter in the universe is made out of positive energy. However, the matter is all attracting itself by gravity. Two pieces of matter that are close to each other have less energy than...