Tuesday, November 24, 2015
100th Anniversary of General-Relativity Discovery
Today's New York Timesmarks the 100th anniversary of Einstein's Theory of General Relativity. As the linked article notes, Einstein and colleagues had published versions of the theory prior to 1915 that weren't quite right. But in November 2015, the theory was finally ready for prime time. What made the theory "general" is that it applied to all situations, including those involving acceleration. Einstein's earlier Special Theory of Relativity was confined to constant speed. My earlier postings on Special and General Relativity can be found in the links section in the right-hand column.
Wednesday, October 21, 2015
New Finding Supports Quantum Entanglement
The New York Times reports on a new European study supporting quantum entanglement, the notion that "objects separated by great distance can instantaneously affect each other’s behavior" (link). The finding appears to counteract one of Einstein's objections to quantum mechanics. My introductory overview of quantum entanglement is available here.
Sunday, October 18, 2015
Book Review: "The Amazing Story of Quantum Mechanics"
University of Minnesota physics professor James Kakalios sets out to tie together three separate threads in his 2010 book The Amazing Story of Quantum Mechanics: A Math-Free Exploration of the Science That Made Our World. These threads are futuristic science-fiction literature from the 1920s, 1930s, and beyond; historical developments in quantum mechanics; and modern-day consumer gadgets.
Occasionally, I would get the feeling the author was delving too single-mindedly into one of the three areas, to the exclusion of the other two. In the end, however, I think all three major topics received their fair share of coverage.
Kakalios gives away a major theme early on: Whereas much futuristic science-fiction predicted scientific-engineering advances in compact energy storage (e.g., so that people could readily fly around with their personal jet-packs), the real advances have come in information storage. Notes Kakalios, "A modest laptop computer currently employs approximately more than a hundred million solid-state transistors for data storage and processing. If all of these transistors were replaced with vacuum tubes [the older technology]... [the result] would yield a vacuum tube computer larger than the White House" (p. XIII).
A key aspect of quantum mechanics is the restriction of certain physical changes to discrete units. As I quoted from a Stanford document in an earlier posting, a hypothetical example would be to "...imagine if someone told you that water could have only integer temperatures as you boiled it. For example, the water could have temperatures of 85º, 86º or 87º, but not 85.7º or 86.5º."
Through much of the book, Kakalios relies on the metaphor of a performing-arts center with orchestra pit, mezzanine, and balcony as the only allowable levels, to illustrate how electrons can be "promoted" up to higher levels, with light (photons) emitted as electrons fall back down (e.g., pp. 178-179, 186). Kakalios presents a fairly lengthy, yet layperson-friendly, description of the Schrӧdinger equation, concluding that "One intriguing consequence of the Schrӧdinger equation is that it explained that electrons in an atom could have only certain energy values, and that all other electronic energies were forbidden" (p. 71).
One example of electrons moving between levels and producing photon emission is glow-in-the-dark objects. Marvels Kakalios, "From such simple quantum mechanical phenomena are totally awesome toys made" (p. 181). Similar principles have allowed hands on wristwatches and alarm clocks to be viewable in the dark, and for lasers to be created.
Advances in solid-state/condensed-matter physics, engineering, and manufacturing, from semiconductors, to diodes (including light-emiting diodes or LED), to the aforementioned transistor have brought a host of devices to the consumer. As the book notes, "Semiconductors make convenient light-detectors, as the separation between the bands of filled and empty states corresponds to energies in the visible portion of the spectrum" (p. 199).* As a result, among other things, we have television remote-controls, smoke-alarms, automatically opening doors, and street lights that come on upon darkness outside. I have long been fascinated by touch-screen technology and Kakalios explains the latest developments in that area, as well.
As the book moves along, the technical aspects get increasingly challenging in my view. I found n- and p-typed semiconductors a bit hard to grasp. Fortunately, there are some YouTube videos that help (for example, here, here, and here).
Finally, Kakalios discusses prospects for future technological advances. One would be quantum computers, which could greatly speed up calculations. If a quantum computer is ever realized, however, "It will be up to all of us to ensure that this technology does not fall into the wrong hands, for who could forget when the evil Decepticons used quantum computers to hack into the Pentagon's secure computer system in the Transformers movie (2007), cracking a code in ten seconds that would take more than two decades for the most power[ful] supercomputer" (p. 244). Other potential advances include expanded use of solar cells for electricity and "high-speed magnetically levitating trains" (p. 254).
If you're a fan of futuristic science fiction, modern technological gadgetry, or quantum mechanics, you'll probably like The Amazing Story of Quantum Mechanics. If you're a fan of all three, you'll love it!
---------
*I initially omitted the closing quotation mark. My apologies for the confusion.
Occasionally, I would get the feeling the author was delving too single-mindedly into one of the three areas, to the exclusion of the other two. In the end, however, I think all three major topics received their fair share of coverage.
Kakalios gives away a major theme early on: Whereas much futuristic science-fiction predicted scientific-engineering advances in compact energy storage (e.g., so that people could readily fly around with their personal jet-packs), the real advances have come in information storage. Notes Kakalios, "A modest laptop computer currently employs approximately more than a hundred million solid-state transistors for data storage and processing. If all of these transistors were replaced with vacuum tubes [the older technology]... [the result] would yield a vacuum tube computer larger than the White House" (p. XIII).
A key aspect of quantum mechanics is the restriction of certain physical changes to discrete units. As I quoted from a Stanford document in an earlier posting, a hypothetical example would be to "...imagine if someone told you that water could have only integer temperatures as you boiled it. For example, the water could have temperatures of 85º, 86º or 87º, but not 85.7º or 86.5º."
Through much of the book, Kakalios relies on the metaphor of a performing-arts center with orchestra pit, mezzanine, and balcony as the only allowable levels, to illustrate how electrons can be "promoted" up to higher levels, with light (photons) emitted as electrons fall back down (e.g., pp. 178-179, 186). Kakalios presents a fairly lengthy, yet layperson-friendly, description of the Schrӧdinger equation, concluding that "One intriguing consequence of the Schrӧdinger equation is that it explained that electrons in an atom could have only certain energy values, and that all other electronic energies were forbidden" (p. 71).
One example of electrons moving between levels and producing photon emission is glow-in-the-dark objects. Marvels Kakalios, "From such simple quantum mechanical phenomena are totally awesome toys made" (p. 181). Similar principles have allowed hands on wristwatches and alarm clocks to be viewable in the dark, and for lasers to be created.
Advances in solid-state/condensed-matter physics, engineering, and manufacturing, from semiconductors, to diodes (including light-emiting diodes or LED), to the aforementioned transistor have brought a host of devices to the consumer. As the book notes, "Semiconductors make convenient light-detectors, as the separation between the bands of filled and empty states corresponds to energies in the visible portion of the spectrum" (p. 199).* As a result, among other things, we have television remote-controls, smoke-alarms, automatically opening doors, and street lights that come on upon darkness outside. I have long been fascinated by touch-screen technology and Kakalios explains the latest developments in that area, as well.
As the book moves along, the technical aspects get increasingly challenging in my view. I found n- and p-typed semiconductors a bit hard to grasp. Fortunately, there are some YouTube videos that help (for example, here, here, and here).
Finally, Kakalios discusses prospects for future technological advances. One would be quantum computers, which could greatly speed up calculations. If a quantum computer is ever realized, however, "It will be up to all of us to ensure that this technology does not fall into the wrong hands, for who could forget when the evil Decepticons used quantum computers to hack into the Pentagon's secure computer system in the Transformers movie (2007), cracking a code in ten seconds that would take more than two decades for the most power[ful] supercomputer" (p. 244). Other potential advances include expanded use of solar cells for electricity and "high-speed magnetically levitating trains" (p. 254).
If you're a fan of futuristic science fiction, modern technological gadgetry, or quantum mechanics, you'll probably like The Amazing Story of Quantum Mechanics. If you're a fan of all three, you'll love it!
---------
*I initially omitted the closing quotation mark. My apologies for the confusion.
Sunday, October 11, 2015
2015 Nobel Physics Prize Goes to Neutrino Researchers
This year's Nobel Prize in Physics has gone to a pair of neutrino researchers, Arthur McDonald (Canada) and Takaaki Kajita (Japan). This article provides an overview of what neutrinos are, their importance to understanding the universe, and the Nobel Prize-winning research.
Monday, March 23, 2015
Restarting of the LHC & Emmy Noether Biography from Vox
The explanatory journalism website Vox has a pair of physics-related articles today:
One previews the restarting of the Large Hadron Collider after a two-year hiatus for upgrades. The article also refreshes our memory on what was previously discovered at the LHC.
The other reviews the life of mathematician/physicist Emmy Noether, including her discoveries on symmetries and conservation, and the gender-discrimination she faced, on the 133rd anniversary of her birth. I wrote about Noether and symmetry back in this 2009 entry.
One previews the restarting of the Large Hadron Collider after a two-year hiatus for upgrades. The article also refreshes our memory on what was previously discovered at the LHC.
The other reviews the life of mathematician/physicist Emmy Noether, including her discoveries on symmetries and conservation, and the gender-discrimination she faced, on the 133rd anniversary of her birth. I wrote about Noether and symmetry back in this 2009 entry.
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