‘Empire of Cotton,’ by Sven Beckert - NYTimes.com

‘Empire of Cotton,’ by Sven Beckert - NYTimes.com:



 "The history of an era often seems defined by a particular commodity. The 18th century certainly belonged to sugar. The race to cultivate it in the West Indies was, in the words of the French Enlightenment writer Guillaume-Thomas de Raynal, “the principal cause of the rapid movement which stirs the Universe.” In the 20th century and beyond, the commodity has been oil: determining events from the Allied partitioning of the Middle East after World War I to Hitler’s drive for Balkan and Caspian wells to the forging of our own fateful ties to the regimes of the Persian Gulf."



'via Blog this'

Markets Hit High in '14 as Bull Run Endured - NYTimes.com

Markets Hit High in '14 as Bull Run Endured - NYTimes.com:



 "An accelerating United States economy trumped problems overseas to lift the stock market to new highs in 2014."



'via Blog this'

Rosewater

Tidings of Comfort - NYTimes.com

Tidings of Comfort - NYTimes.com:



"Maybe I’m just projecting, but Christmas seemed unusually subdued this year. The malls seemed less crowded than usual, the people glummer. There was even less Muzak in the air. And, in a way, that’s not surprising: All year Americans have been bombarded with dire news reports portraying a world out of control and a clueless government with no idea what to do."



'via Blog this'

That Old PlayStation Can Aid Science - NYTimes.com

That Old PlayStation Can Aid Science - NYTimes.com:



 "This spring, Gaurav Khanna noticed that the University of Massachusetts Dartmouth physics department was more crowded than usual. Why, he wondered, were so many students suddenly so interested in science?"



'via Blog this'

Black Hills

Attack Is Suspected as North Korean Internet Collapses - NYTimes.com

Attack Is Suspected as North Korean Internet Collapses - NYTimes.com:



"SAN FRANCISCO — North Korea’s already tenuous links to the Internet went completely dark on Monday after days of instability, in what Internet monitors described as one of the worst North Korean network failures in years."



'via Blog this'

Putin, Neocons and the Great Illusion - NYTimes.com

Putin, Neocons and the Great Illusion - NYTimes.com:



"More than a century has passed since Norman Angell, a British journalist and politician, published “The Great Illusion,” a treatise arguing that the age of conquest was or at least should be over. He didn’t predict an end to warfare, but he did argue that aggressive wars no longer made sense — that modern warfare impoverishes the victors as well as the vanquished."



'via Blog this'

[1410.8724] Proton transport through one atom thick crystals

[1410.8724] Proton transport through one atom thick crystals:



"Graphene is impermeable to all gases and liquids, and even such a small atom as hydrogen is not expected to penetrate through graphene's dense electronic cloud within billions of years. Here we show that monolayers of graphene and hexagonal boron nitride (hBN) are unexpectedly permeable to thermal protons, hydrogen ions under ambient conditions. As a reference, no proton transport could be detected for a monolayer of molybdenum disulfide, bilayer graphene or multilayer hBN. At room temperature, monolayer hBN exhibits the highest proton conductivity with a low activation energy of about 0.3 eV but graphene becomes a better conductor at elevated temperatures such that its resistivity to proton flow is estimated to fall below 10^-3 Ohm per cm2 above 250 C. The proton barriers can be further reduced by decorating monolayers with catalytic nanoparticles. These atomically thin proton conductors could be of interest for many hydrogen-based technologies."



'via Blog this'

Electron Mass by Mario Rabinowitz

Electron Acceleration Gains Electron Mass

Whether It Radiates or Not .

For an accelerated electron, electrodynamics yields two self-forces on the  electron, a radiation reaction force and a previously unappreciated retardation force. These forces are examined and compared.  The traditional radiation reaction force exists only when there is radiation that produces a time rate of change of acceleration.  A retardation force results whenever the electron’s self-field changes due to acceleration, and is present even if there is no radiation and the acceleration is constant.  It is found that the retardation force on the electron is >>> the radiation reaction force.  In a new way, this circumvents problems of pre-acceleration, and energy run-away solutions. It is predicted that because the retardation force manifests itself inertially,  makes the dynamic mass of any accelerated subatomic singly charged particle about 1/137 higher than its rest mass.    

  It can be freely downloaded at

http://dx.doi.org/10.12988/astp.2014.411142   .

Border Patrol Apprehensions Show a Shift in Migration Patterns - NYTimes.com

Border Patrol Apprehensions Show a Shift in Migration Patterns - NYTimes.com:



 "For the first time in at least two decades, fewer migrants from Mexico were caught crossing into the United States in 2014 than people from other countries, marking a major shift in illegal migration into the country, according to annual figures published Friday by the Department of Homeland Security."



'via Blog this'

A ‘Brave’ Move by Obama Removes a Wedge in Relations With Latin America - NYTimes.com

A ‘Brave’ Move by Obama Removes a Wedge in Relations With Latin America - NYTimes.com:



"BUENOS AIRES — President Obama has been lambasted for spying in Brazil, accused of being a warmonger by Bolivia, dismissed as a “lost opportunity” by Argentina, and taunted in Nicaragua by calls for Latin America to draw up its own list of state sponsors of terrorism — with the United States in the No. 1 spot."



'via Blog this'

Celebrating the Legacy of a Chinese Explorer - NYTimes.com

Celebrating the Legacy of a Chinese Explorer - NYTimes.com:



 "MALACCA, Malaysia — When Zheng He, the seafaring eunuch explorer of the Chinese Ming dynastic court, guided boats packed with porcelain to Africa and the Arabian Peninsula, he brought giraffes back to China and founded stockades along the shipping lanes of Southeast Asia."



'via Blog this'

Kepler Spacecraft Finds New ‘Super-Earth’ 180 Light-Years Away - NYTimes.com

Kepler Spacecraft Finds New ‘Super-Earth’ 180 Light-Years Away - NYTimes.com:



 "A year and a half after a pointing failure threatened to derail its epochal search for worlds beyond our solar system, NASA’s Kepler spacecraft has bagged another planet, astronomers announced on Thursday."



'via Blog this'

Putin’s Bubble Bursts - NYTimes.com

Putin’s Bubble Bursts - NYTimes.com:



"If you’re the type who finds macho posturing impressive, Vladimir Putin is your kind of guy. Sure enough, many American conservatives seem to have an embarrassing crush on the swaggering strongman. “That is what you call a leader,” enthused Rudy Giuliani, the former New York mayor, after Mr. Putin invaded Ukraine without debate or deliberation."



'via Blog this'

A Picture Captures Planets Waiting to Be Born - NYTimes.com

A Picture Captures Planets Waiting to Be Born - NYTimes.com:



 "We might be stardust, Joni Mitchell sang of Woodstock in 1969, echoing what was already a half-century of hard-headed astronomical truth. But astronomers have struggled to understand just exactly how stardust goes from being cosmic smog, littering the lanes of the galaxy, to planets and people."



'via Blog this'

A New Beginning With Cuba - NYTimes.com

A New Beginning With Cuba - NYTimes.com:



 "Following months of secret negotiations with the Cuban government, President Obama on Wednesday announced sweeping changes to normalize relations with Havana, a bold move that ends one of the most misguided chapters in American foreign policy.

"



'via Blog this'

FACT SHEET: Charting a New Course on Cuba | The White House

FACT SHEET: Charting a New Course on Cuba | The White House:



"Today, the United States is taking historic steps to chart a new course in our relations with Cuba and to further engage and empower the Cuban people.  We are separated by 90 miles of water, but brought together through the relationships between the two million Cubans and Americans of Cuban descent that live in the United States, and the 11 million Cubans who share similar hopes for a more positive future for Cuba. "



'via Blog this'

U.S. and Cuba, in Breakthough, Resume Diplomatic Relations - NYTimes.com

U.S. and Cuba, in Breakthough, Resume Diplomatic Relations - NYTimes.com:



"WASHINGTON — The United States will restore full diplomatic relations with Cuba and open an embassy in Havana for the first time in more than a half-century after the release of an American contractor held in prison for five years, American officials said Wednesday."



'via Blog this'

U.S. and Cuba to Start Talks on Normalizing Relations - NYTimes.com

U.S. and Cuba to Start Talks on Normalizing Relations - NYTimes.com:



"WASHINGTON — The United States will open talks with Cuba aimed at restoring full diplomatic relations and opening an embassy in Havana for the first time in more than a half century after the release of an American contractor held in prison for five years, American officials said Wednesday."



'via Blog this'

Methane Is Found on Mars, Raising Hope of Life There Now - NYTimes.com

Methane Is Found on Mars, Raising Hope of Life There Now - NYTimes.com:



"SAN FRANCISCO — Life on Mars? Today? The notion may not be so far-fetched after all."



'via Blog this'

Obama Will Approve New Sanctions Against Russia for Ukraine Actions - NYTimes.com

Obama Will Approve New Sanctions Against Russia for Ukraine Actions - NYTimes.com:



"WASHINGTON — President Obama has decided to sign legislation imposing further sanctions on Russia and authorizing additional aid to Ukraine, despite concerns that it will complicate his efforts to maintain a unified front with European allies, the White House said on Tuesday."



'via Blog this'

Dodd-Frank Damaged in the Budget Bill - NYTimes.com

Dodd-Frank Damaged in the Budget Bill - NYTimes.com:



"On Wall Street, 2010 was the year of “Obama rage,” in which financial tycoons went ballistic over the president’s suggestion that some bankers helped cause the financial crisis. They were also, of course, angry about the Dodd-Frank financial reform, which placed some limits on their wheeling and dealing."



'via Blog this'

Undocumented Immigrants Line Up for Door Opened by Obama - NYTimes.com

Undocumented Immigrants Line Up for Door Opened by Obama - NYTimes.com:



"LOS ANGELES — They pushed strollers, tugged toddlers and streamed into the convention center in the heart of this city on Sunday, thousands of immigrants here illegally and anxious to find out if they could gain protection from deportation under executive actions by President Obama."



'via Blog this'

Thomas Friedman

I WAS just about to go with a column that started like this: When they write the history of the global response to climate change, 2014 could well be seen as the moment when the balance between action and denial tipped decisively toward action. That’s thanks to the convergence of four giant forces: São Paulo, Brazil, went dry; China and the United States together went green; solar panels went cheap; and Google and Apple went home.

NYT

196 Nations Near Preliminary Climate Change Deal - NYTimes.com

196 Nations Near Preliminary Climate Change Deal - NYTimes.com:



"LIMA, Peru — Negotiators from around the globe were haggling Saturday over the final elements of a draft climate change deal that would, for the first time in history, commit every nation to cutting its greenhouse gas emissions — yet would still fall far short of what is needed to stave off the dangerous and costly early impacts of global warming."



'via Blog this'

Strange Climate Event: Warmth Toward U.S. - NYTimes.com

Strange Climate Event: Warmth Toward U.S. - NYTimes.com:



"LIMA, Peru — When it comes to global warming, the United States has long been viewed as one of the world’s worst actors. American officials have been booed and hissed during international climate talks, bestowed with mock “Fossil of the Day” awards for resisting treaties, and widely condemned for demanding that other nations cut their fossil fuel emissions while refusing, year after year, to take action at home.

"



'via Blog this'

In Mexico, a Growing Gap Between Political Class and Calls for Change - NYTimes.com

In Mexico, a Growing Gap Between Political Class and Calls for Change - NYTimes.com:



"MEXICO CITY — As the Nobel Peace Prize was being awarded in Oslo this week, a young man dashed on stage, unfurled a Mexican flag streaked with red paint and begged for help for his country because more than 40 college students have been missing for months after clashing with the police."



'via Blog this'

Flood-Causing Deluge Amounts to Just Drops in California Drought - NYTimes.com

Flood-Causing Deluge Amounts to Just Drops in California Drought - NYTimes.com:



 "The strong Pacific storm that left Northern California a sodden mess will not have much impact on the state’s historic drought, meteorologists said Friday."



'via Blog this'

The C Programming Language by K&R

Chapter 1: A tutorial introduction

Let us begin with a quick introduction to C. Our aim is to show the essential elements of the language in real programs, but without getting bogged down in details, formal rules, and exceptions. At this point, we are not trying to be complete or even precise (save that the examples are meant to be correct). We want to get you as quickly as possible to the point where you can write useful programs, and to do that we have to concentrate on the basics: variables, and constants, arithmetic, control flow, functions, and the rudiments of input and output. We are quite intentionally leaving out of this chapter features of C which are of vital importance for writing bigger programs. These include pointers, structures, most of C's rich set of operators, several control flow statements, and myriad details.

This approach has its drawbacks, of course. Most notable is that the complete story on any  particular language feature is not found in a single place, and the tutorial, by being brief, may also mislead. And because they can not use the full power of C, the examples are not as concise and elegant as they might be. We have tried to minimize these effects, but be warned.

Another drawback is that later chapters will necessarily repeat some of this chapter. We hope that the repetition will help you more than it annoys.

In any case, experienced programmers should be able to extrapolate from the material in this chapter to their own programming needs. Beginners should supplement it by writing small, similar programs of their own. Both groups can use it as a framework on which to hang the more detailed descriptions that begin in Chapter 2.

Chapter 2: Types, operators and expressions

Variables and constants are the basic data objects manipulated in a program. Declarations list the variables to be used, and state what type they have and perhaps what their initial values are. Operators specify what is to be done to them. Expressions combine variables and constants to produce new values. These are the topics of this chapter.

Chapter 3: Control flow

The control flow statements of a language specify the order in which computations are done. We have already met the most common control flow constructions of C in earlier examples, here we will complete the set, and be more precise about the ones discussed before.

Chapter 4: Functions and program structure

Functions break large computing tasks into smaller ones, and enable people to build on what others have done instead of starting over from scratch. Appropriate functions can often hide details of operation from parts of the program that don't need to know about them, thus clarifying the whole, and easing the pain of making changes.

C has been designed to make functions efficient and easy to use; C programs generally consist of numerous small functions rather than a few big ones. A program may reside on one or more source files in any convenient way; the source files may be compiled separately and loaded together, along with previously compiled functions from libraries. We will not go into that process here, since the details vary according to the local system.

Most programmers are familiar with "library" functions for input and output (getchar, putchar) and numerical computation (sin, cos, sqrt). In this chapter we will show more about writing new functions.

Chapter 5: Pointers and arrays

A pointer is a variable that contains the address of another variable. Pointers are very much used in C, partly because they are sometimes the only way to express a computation, and partly because they usually lead to more compact and efficient code than can be obtained in other ways.

Pointers have been lumped with the goto statement as a marvelous way to create impossible-to-understand programs. This is certainly true when they are used carelessly, and it is easy to create pointers that point somewhere unexpected. With discipline, however, pointers can also be used to achieve clarity and simplicity. This is the aspect that we will try to illustrate.

Chapter 6: Structures

A structure is a collection of one or more variables, possibly of different types, grouped together under a single name for convenient handling. (Structures are called "records" in some languages, most notably Pascal.)

The traditional example  of a structure is the payroll record: an "employee" is described by a set of attributes such as name, address, social security number, salary, etc. Some of these in turn could be structures: a name has several components, as does and address and even a salary.

Structures help to organize complicated data, particularly in large programs, because in many situations they permit a group of related variables to be treated as a unit instead of as separate entities. In this chapter we will try to illustrate how structures are used.  The programs we will use are bigger than many of the others in the book, but still of moderate size.

Chapter 7: Input and output

Input and output facilities are not part of the C language so we have de-emphasized them in our presentation thus far. Nonetheless, real programs do interact with their environment in much more complicated ways than those we have shown before. In this chapter we will describe "the standard I/O library," a set of functions designed to provide a standard I/O system for C programs. The functions are intended to present a convenient programming interface, yet reflect only operations that can be provided on most modern operating systems. The routines are efficient enough that users should seldom feel the need to circumvent them "for efficiency" regardless of how critical the application. Finally, the routines are meant to be "portable," in the sense that they will exist in compatible form on any system where C exists, and that programs which confine their system interactions to facilities provided by the standard library can be moved from one system to another essentially without change.

We will not try to describe the entire I/O library here; we are more interested in showing the essentials of writing C programs that interact with their operating environments.

Browser Wars

Wikipedia

Chrome

Mozilla

In the early 90s, Mosaic was a software product for scientific visualization. Marc Andreessen , developed it at the University of Illinois, at Urbana/Champaign. It was a tool to help astrophysicists with big data sets, both the result of calculations, and observations. Soon it was realized that this, so-called "browser", could help the general public to navigate the Internet, which had recently been freed by the Department of Defense, at the end of the Cold War. There was a big increase in the number of Internet Service Providers. I got my first home connection through America Online, which I still use.

To some, it became clear, that personal computer companies, were in danger of becoming obsolete. Thus we went from the Cold War, to the Browser Wars.

The main players were Microsoft, and Netscape, the company spearheaded by Andreessen. Netscape lost to the monopolistic forces behind Microsoft. Nevertheless, due to the lack of vision of Bill Gates and Paul Allen, two young scientists from Stanford University, Sergei Brin, and Larry Page, created a killer application, the Search Engine powering Google.

Now Google is in its way to becoming the bigger company, that Microsoft never was.

SNMP Config for CUPS

snmp.conf(5)                                                                                   Apple Inc.                                                                                  snmp.conf(5)

NAME
       snmp.conf - snmp configuration file for cups

DESCRIPTION
       The  snmp.conf  file  configures  how  the standard CUPS network backends (http, https, ipp, ipps, lpd, snmp, and socket) access printer information using SNMPv1 and is normally located in the
       /etc/cups directory. Each line in the file can be a configuration directive, a blank line, or a comment. Comment lines start with the # character.

       The Community and DebugLevel directives are used by all backends. The remainder apply only to the SNMP backend (cups-snmp(8)).

DIRECTIVES
       The following directives are understood by the CUPS network backends. Consult the on-line help for detailed descriptions:

       Address @IF(name)

       Address @LOCAL

       Address address
            Sends SNMP broadcast queries to the specified address(es). There is no default for the broadcast address.

       Community name
            Specifies the community name to use. Only a single community name may be specified. The default community name is "public".

       DebugLevel number
            Specifies the logging level from 0 (none) to 3 (everything). Typically only used for debugging (thus the name). The default debug level is 0.

       DeviceURI "regular expression" device-uri [... device-uri]
            Specifies one or more device URIs that should be used for a given make and model string. The regular expression is used to match the detected make and model, and the  device  URI  strings
            must be of the form "scheme://%s[:port]/[path]", where "%s" represents the detected address or hostname. There are no default device URI matching rules.

       HostNameLookups on

       HostNameLookups off
            Specifies whether the addresses of printers should be converted to hostnames or left as numeric IP addresses. The default is "off".

       MaxRunTime seconds
            Specifies the maximum number of seconds that the SNMP backend will scan the network for printers. The default is 120 seconds (2 minutes).

SEE ALSO
       cups-snmp(8),
       http://localhost:631/help

COPYRIGHT
       Copyright 2007-2013 by Apple Inc.

23 April 2012                                                                                     CUPS                                                                                     snmp.conf(5)
 Manual page cups-snmp.conf(5) line 1/51 (END) (press h for help or q to quit)

Mike Sweet

Blog

Recovery at Last? - NYTimes.com

Recovery at Last? - NYTimes.com:



"Last week we got an actually good employment report — arguably the first truly good report in a long time. The U.S. economy added well over 300,000 jobs; wages, which have been stagnant for far too long, picked up a bit. Other indicators, like the rate at which workers are quitting (a sign that they expect to find new jobs), continue to improve. We’re still nowhere near full employment, but getting there no longer seems like an impossible dream."



'via Blog this'

[1409.8239] MetaCache: Efficient Metadata Caching in Linux file system

[1409.8239] MetaCache: Efficient Metadata Caching in Linux file system:



"Nowadays, Linux file systems have to manage millions of tiny files for different applications, and face with higher metadata operations. So how to provide such high metadata performance with such enormous number of files and large scale directories is a big challenge for Linux file system. We viewed that metadata lookup operations dominate metadata workload and incur low metadata performance. In this paper, we present a metadata cache to accelerate metadata access for Linux file system. Through this optimization, the Linux file system (such as EXT2, EXT4, BTRFS, etc.) can gain improvement in read rates as well as write rates."



'via Blog this'

[1412.1114] Easy Hyperparameter Search Using Optunity

[1412.1114] Easy Hyperparameter Search Using Optunity:



Optunity is a free software package dedicated to hyperparameter optimization. It contains various types of solvers, ranging from undirected methods to direct search, particle swarm and evolutionary optimization. The design focuses on ease of use, flexibility, code clarity and interoperability with existing software in all machine learning environments. Optunity is written in Python and contains interfaces to environments such as R and MATLAB. Optunity uses a BSD license and is freely available online at this http URL"



'via Blog this'

Feynman Checkerboard as a Model of Discrete Space-Time

Feynman Checkerboard as a Model of Discrete Space-Time:



"This paper began with Feynman's checkerboard, and concluded with particles forming an interference pattern. Perhaps this should not be surprising, as Feynman predicted this result in the early 1940's."



'via Blog this'

[1411.3013] Bayesian Evidence and Model Selection

[1411.3013] Bayesian Evidence and Model Selection:



"In this paper we review the concept of the Bayesian evidence and its application to model selection. The theory is presented along with a discussion of analytic, approximate and numerical techniques. Application to several practical examples within the context of signal processing are discussed."



'via Blog this'

[1411.2163] Information-Based Physics, Influence, and Forces

[1411.2163] Information-Based Physics, Influence, and Forces:



"In recent works, Knuth and Bahreyni have demonstrated that the concepts of space and time are emergent in a coarse-grained model of direct particle-particle influence. In addition, Knuth demonstrated that observer-made inferences regarding the free particle, which is defined as a particle that influences others, but is not itself influenced, result in a situation identical to the Feynman checkerboard model of the Dirac equation. This suggests that the same theoretical framework that gives rise to an emergent spacetime is consistent with quantum mechanics. In this paper, we begin to explore the effect of influence on the emergent properties of a particle. This initial study suggests that when a particle is influenced, it is interpreted as accelerating in a manner consistent with special relativity implying that, at least in this situation, influence can be conceived of as a force."



'via Blog this'

Putin, in Defeat, Diverts Pipeline - NYTimes.com

Putin, in Defeat, Diverts Pipeline - NYTimes.com:



"MOSCOW — President Vladimir V. Putin said Monday that he would scrap Russia’s South Stream gas pipeline, a grandiose project that was once intended to establish the country’s dominance in southeastern Europe but instead fell victim to Russia’s increasingly toxic relationship with the West."



'via Blog this'

Anthony D. Marshall, Astor Son Who Was Convicted in Swindle, Dies at 90 - NYTimes.com

Anthony D. Marshall, Astor Son Who Was Convicted in Swindle, Dies at 90 - NYTimes.com:



"Anthony D. Marshall, the only son of the philanthropist-socialite Brooke Astor, who with one of her former lawyers was found guilty of criminal charges that they swindled millions from his mother after she was stricken with Alzheimer’s disease, died on Sunday in Manhattan. He was 90."



'via Blog this'

A Week Later, Protests Continue Over Ferguson Decision - NYTimes.com

A Week Later, Protests Continue Over Ferguson Decision - NYTimes.com:



"ST. LOUIS — Across the country on Monday, people walked out of their jobs and classrooms with their hands raised, the gesture that has become a symbol for the death of Michael Brown, the unarmed African-American teenager shot by a white police officer in Ferguson, Mo."



'via Blog this'

Avi Loeb Ponders the Early Universe, Nature and Life - NYTimes.com

Avi Loeb Ponders the Early Universe, Nature and Life - NYTimes.com:



 "CAMBRIDGE, Mass. — Among astrophysicists, Abraham Loeb is known for his creative and prolific attempts to understand the early universe."



'via Blog this'

A Robot Exhibit at MoMath Aims to Bring Math to Life - NYTimes.com

A Robot Exhibit at MoMath Aims to Bring Math to Life - NYTimes.com:



"Behind a black curtain in a downstairs corner of the National Museum of Mathematics in Manhattan (known as MoMath), a small group of mathematicians, designers and engineers was hard at work — laughing, shouting, clapping and having a blast, while being chased by robots."



'via Blog this'

Protests Around the Country Mark the Moment of Ferguson Shooting - NYTimes.com

Protests Around the Country Mark the Moment of Ferguson Shooting - NYTimes.com:



"Students and others around the country staged protests on Monday in solidarity with Michael Brown, the black unarmed teenager whose shooting death in Ferguson, Mo., on Aug. 9 at the hands of a white police officer has set off months of unrest around the country.

"



'via Blog this'

[1411.7569] Exactly solvable deformations of the oscillator and Coulomb systems and their generalization

[1411.7569] Exactly solvable deformations of the oscillator and Coulomb systems and their generalization:



"We present two maximally superintegrable Hamiltonian systems Hλ and Hη that are defined, respectively, on an N-dimensional spherically symmetric generalization of the Darboux surface of type III and on an N-dimensional Taub-NUT space. Afterwards, we show that the quantization of Hλ and Hη leads, respectively, to exactly solvable deformations (with parameters λ and η) of the two basic quantum mechanical systems: the harmonic oscillator and the Coulomb problem. In both cases the quantization is performed in such a way that the maximal superintegrability of the classical Hamiltonian is fully preserved. In particular, we prove that this strong condition is fulfilled by applying the so-called conformal Laplace-Beltrami quantization prescription, where the conformal Laplacian operator contains the usual Laplace-Beltrami operator on the underlying manifold plus a term proportional to its scalar curvature (which in both cases has non-constant value). In this way, the eigenvalue problems for the quantum counterparts of Hλ and Hη can be rigorously solved, and it is found that their discrete spectrum is just a smooth deformation (in terms of the parameters λ and η) of the oscillator and Coulomb spectrum, respectively. Moreover, it turns out that the maximal degeneracy of both systems is preserved under deformation. Finally, new further multiparametric generalizations of both systems that preserve their superintegrability are envisaged."



'via Blog this'