The Amazing Story of Quantum Mechanics Part 7

CHAPTER TWENTY-ONE.

Seriously, Where's My Jet Pack?

As mentioned at the very start of our narrative, science fiction pulp writers expected that the future would bring a new era in energy production and storage. Instead, it was data manipulation that underwent a profound transformation, enabled by the discoveries of quantum mechanics.

Why is a new type of energy-delivery system needed before jet packs and flying cars become commercially viable? Let's stipulate that we are not invoking any violations of the laws of physics, such as the discovery of "cavorite" or some other miraculous material with antigravity properties. Thus, our jet pack must provide a downward thrust, equal to a person's weight, in order to lift the person off the ground. Consider how much energy it takes to lift a 180-pound person 330 feet (one-sixteenth of a mile) up in the air. Just to get up there, neglecting any energy needed to jet from place to place, would require an energy expenditure of a little over eighty thousand Joules, which is equivalent to 0.5 trillion trillion electron Volts.

Recall that nearly every chemical reaction involves energy transfers on the order of an electron Volt. Thus, to lift a person over a twenty-story building involves roughly a trillion trillion molecules of fuel. But that's not actually as much as it seems, for there are approximately that many atoms in twenty cubic centimeters of any solid (recall that a cubic centimeter is about the size of a sugar cube). A gallon of fuel contains nearly four thousand cubic centimeters, capable of producing over a hundred trillion trillion electron Volts of energy. If this is the case, why are we still driving to work?

The problem is-what goes up must come down. As soon as our jet pack stops expending energy to maintain our large potential energy above ground, back to Earth we return. Thus, every second we spend in the air, we must continue to burn through our stored chemical energy. The rate at which we use up fuel will depend on the particular mechanism by which we achieve an upward thrust, but for most energy supplies, our trip will be over in a minute or two. We can indeed take jet packs to work, provided we live no more than a few blocks from our office.

Note that the largest expenditure in energy is overcoming gravity. It takes more than eighty thousand Joules to get us up in the air. Flying at forty miles per hour, in contrast, calls for a kinetic energy of only thirteen thousand Joules (neglecting the work we must do to overcome air resistance). This is why we don't have flying cars. Your gas mileage would be nonexistent if the vast majority of the fuel you carried went toward lifting you up off the ground, with hardly any left over to get you to your destination (sort of defeats the whole purpose of a car, flying or otherwise).

There have been improvements in the energy content of stored fuel, and prototype jet packs have been able to keep test pilots aloft for more than a minute, but ultimately, the longer the flight, the more fuel needed (and the heavier the jet pack will be). Of course, there are alternatives to chemical-fuel reactions to achieve thrust and lift. One could use a nuclear reaction, which, as we saw in Section 3, yields roughly a million times more energy per atom than chemical combustion, but the idea of wearing even a licensed nuclear power plant on your back is less than appealing (except possibly for the Ghostbusters).

In the 2008 film Iron Man, Tony Stark designs a suit of armor that contains a host of high-tech gadgets, all of which are within the realm of physical plausibility-with one big exception. The one miracle exception from the laws of nature that the film invokes is the "arc reactor" that powers Stark's high-tech exoskeleton. This device is a cylinder about the size of a hockey puck and is capable of producing "three GigaWatts of power,"75 sufficient to keep a real-world jet pack aloft and flying for hours. Sadly, we have no way of producing such compact, lightweight, high-energy-content power cells.

Had the revolution in energy antic.i.p.ated by the science fiction pulp magazines indeed occurred and we employed personal jet packs to get to work or the corner grocery store, powered by some exotic energy source, the need for conventional fossil fuels would of course be dramatically reduced, with a concurrent dramatic shift in geopolitical relations. There is one important use of potential jet-pack technology that does not involve transportation but rather thirst quenching, that would have an immediate beneficial impact.

According to the World Health Organization, as of 2009, 40 percent of the world's population suffers from a scarcity of potable fresh water. The most straightforward method to convert seawater to fresh water involves boiling the salt water and converting the liquid water to steam, which leaves the salts behind in the residue. This is, after all, what occurs during evaporation from the oceans, which is why rainwater is salt free. The amount of energy needed to boil a considerable amount of water is not easily provided by solar cells, but if one had a power supply for a fully functioning jet pack, the lives of more than two billion people would be profoundly improved, even if everyone's feet stayed firmly planted on the ground.

Can quantum mechanics help in the production of energy, so that the jet-pack dreams of the 1930s can be at long last realized? Possibly. Global consumption of energy, which in 2005 was estimated to be sixteen trillion Watts, will certainly increase in the future, with many experts projecting that demand will grow by nearly 50 percent in the next twenty years. One strategy to meet this additional need involves the construction of a new power plant, capable of producing a gigaWatt of power, at the rate of one new facility every day for the next two decades. This does not seem likely to happen.

Another approach is to tap the vast amount of energy that is, for the most part, ignored by all nations-sunlight. The surface of the Earth receives well over a hundred thousand trillion Watts of power, more than six thousand times the total global energy usage and more than enough to meet the world's energy needs for decades to come. As described in Chapter 16, the simple diode, comprised of a junction between one semiconductor with impurities that donate excess electrons and a second semiconductor with impurities that donates holes, can function as a solar cell. When the diode absorbs a photon, an electron is promoted into the upper band, leaving a mobile hole in the lower filled band. These charge carriers feel a force from the strong internal electric field at the pn junction, and a current can be drawn out of the device, simply as a result of exposing it to sunlight. Work is under way to improve the conversion efficiency of these devices-that is, to maximize the current that results for a given intensity of sunlight. But even using current cells, with conversion efficiencies of only 10 percent (that is, 90 percent of the energy that shines on the solar cell does not lead to electrical power), we could provide all the electricity needs of the United States with an array of solar cells of only one hundred miles by one hundred miles.

The problem is, we don't have enough solar cells on hand to cover a one-hundred-mile-by-one-hundred-mile grid, and at the present production capacity it would take many years to fabricate these devices. Moreover, even if the solar cells existed, we would need to get the electrical power from bright sunny locales to the gloomy cities with large population densities. Here again, quantum mechanics may help.

In Chapter 13 we saw that at low temperatures certain metals become superconductors, when their electrons form bound pairs through a polarization of the positive ions in the metal lattice. Electrons have intrinsic angular momentum of /2 and individually obey Fermi-Dirac statistics (Chapter 12) that stipulate that no two electrons can be the same quantum state. When the electrons in a metal at low temperature pair up, they create composite charge carriers that have a net total spin of zero. These paired electrons obey Bose-Einstein statistics, and as the temperature is lowered they condense into a low energy state. If the temperature of the solid is low enough, then for moderate currents there is not enough energy to scatter the electrons out of this lowest energy state, and they can thus carry current without resistance. This phenomenon-superconductivity-is an intrinsically quantum mechanical effect and is observed only in metals at extremely low temperatures, below -420 degrees Fahrenheit.

At least-that was the story until 1986. In that year two scientists, Johannes Bednorz and Karl Muller, at the IBM research laboratory in Zurich, Switzerland, reported their discovery of a ceramic that became a superconductor at -400 degrees Fahrenheit. That's still very cold, but at the time it set a record for the highest temperature at which superconductivity was observed. Once the scientific community knew that this cla.s.s of materials, containing copper, oxygen, and rare Earth metals, could exhibit superconductivity, the race was on, and research labs around the world tried a wide range of elements in a host of combinations. A year later a group of scientists from the University of Houston and University of Alabama discovered a compound of yttrium, barium, copper, and oxygen that became a full-fledged superconductor at a balmy -300 degrees Fahrenheit. Liquid nitrogen, used in many dermatologists' offices for the treatment of warts, is 20 degrees colder at -321 Fahrenheit. These materials are referred to as "high-temperature superconductors," as their transition into a zero resistance state can be induced using a refrigerant found in many walk-in medical clinics. There is no definitive explanation for how these materials are able to become superconductors at such relatively toasty temperatures, and their study remains an active and exciting branch of solid-state physics. The most promising models to account for this effect invoke novel mechanisms that quantum mechanically induce the electrons in these solids to form a collective ground state.

High-temperature superconductors would be ideal to transmit electricity generated from a remote bank of solar cells or windmills to densely populated regions where the power is needed. While it would need to be kept cool, liquid nitrogen is easy to produce, and when purchased for laboratory needs it is cheaper than milk (and certainly cheaper than bottled water). Unfortunately, to date challenging materials-science issues limit the currents that can be carried by these ceramics, such that if we were to use them for transmission lines they would cease to become superconductors and would in fact have resistances higher than those of ordinary metals.

If these problems are ever solved, then along with transmitting electrical power, these innovations may help transportation undergo a revolution as well. As discussed in Chapter 13, in addition to carrying electrical current with no resistance, superconductors are perfect diamagnets, completely repelling any externally applied magnetic field. The material sets up screening currents that cancel out the external field trying to penetrate the superconductor, and as there is no resistance to current flow, these screening currents can persist indefinitely. If high-temperature superconductors can be fabricated that are able to support high enough currents to block out large enough magnetic fields, then high-speed magnetically levitating trains are possible, where the major cost involves the relatively cheap and safe liquid nitrogen coolant.

Bednorz and Muller won the n.o.bel Prize in Physics just one year after they published their discovery of high-temperature superconductivity in ceramics. However, more than twenty years later, the trains still do not levitate riding on rails composed of novel copper oxide compounds. Unlike giant magnetoresistance and the solid-state transistor, both of which went from the research lab to practical applications in well under a decade, there are no preexisting consumer products for which raising the transition temperature of a superconductor would make a significant difference. Nevertheless, research on these materials continues, and someday we may have high-temperature superconductors overhead in our transmission lines and underfoot on our rail lines.

Another untapped source of energy that quantum mechanics- based devices may be able to exploit in the near future involves waste. I speak here not of garbage but of waste heat, generated as a by-product of any combustion process.

Why is heat wasted under the hood of your car? Heat and work are both forms of energy. Work, in physics terms, involves a force applied over a given distance, as when the forces exerted by the collisions of rapidly moving gas molecules lift a piston in a car engine. Heat in physics refers to the transfer of energy between systems having different average energy per atom. Bring a solid where the atoms are vigorously vibrating in contact with another where the atoms are slowly shaking, and collisions and interactions between the const.i.tuent atoms result in the more energetic atoms slowing down while the sluggish atoms speed up. We say that the first solid initially had a higher temperature while the second had a lower temperature, and that through collisions they exchange heat until they eventually come to some common temperature. We can do work on a system and convert all of it to heat, but the Second Law of Thermodynamics informs us that we can never, with 100 percent efficiency, transform a given amount of heat into work.

Why not? Because of the random nature of collisions. Consider the molecules in an automobile piston, right before the ignition spark and compression stroke cause the gasoline and oxygen molecules to undergo combustion. They are zipping in all directions, colliding with each other and the walls and bottom and top of the cylinder. The pressure is uniform on all surfaces in the cylinder. Following combustion, the gas-oxygen mixture undergoes an explosive chemical reaction, yielding other chemicals and releasing heat; that is, the reaction products have greater kinetic energy than the reactants had before the explosion. This greater kinetic energy leads to a greater force being exerted on the head of the piston as the gas molecules collide with it. This larger force raises the piston and, through a clever system of shafts and cams, converts this lifting to a rotational force applied to the tires. But the higher gas pressure following the chemical explosion pushes on all surfaces of the cylinder, though only the force on the piston head results in useful work. The other collisions wind up warming the walls and piston of the cylinder, and from the point of view of getting transportation from the gasoline, this heat is "wasted."

When heat is converted to work, the Second Law of Thermodynamics quantifies how much heat will be left over. In an automobile, in the best-case scenario, one can expect to convert only one-third of the available chemical energy into energy that moves the car, and very few auto engines are even that efficient. There's a lot of energy under the hood that is not being effectively utilized. Similarly, cooling towers for power plants eject vast quant.i.ties of heat into the atmosphere. It is estimated that more than a trillion Watts of energy are wasted every year in the form of heat not completely converted to work. This situation may change in the future, thanks to solid-state devices called "thermoelectrics." These structures convert temperature differences into voltages and are the waste-heat version of solar cells (also known as "photovoltaic" devices) that convert light into voltages.

Thermoelectrics make use of the same physics that enables solid-state thermometers to record a temperature without gla.s.s containers of mercury. Consider two different metals brought into contact. We have argued that metals can be viewed as lecture halls where only half of the possible seats are occupied, so that there are many available empty seats that can be occupied if the electrons absorb energy from either light, or applied voltages, or heat. Different metals will have different numbers of electrons in the partially filled lower band. Think about two partially filled auditoriums, each with different numbers of people sitting in the seats, separated by a removable wall, as in some hotel ballrooms. One auditorium has two hundred people, while the other has only one hundred. Now the wall separating them is removed, creating one large auditorium. As everyone wants to sit closer to the front, fifty people from the first room move into vacant seats in the other, until each side has one hundred and fifty people sitting in it. But both metals were electrically neutral before the wall was removed. Adding fifty electrons to the small room creates a net negative charge, while subtracting fifty electrons from the first room yields a net positive charge. A voltage thus develops at the juncture between the two metals, just by bringing them into electrical contact. If there are significant differences in the arrangements on the rows of seats in each side, then as the temperature is raised the number of electrons on each side may vary, leading to a changing voltage with temperature. In this way, by knowing what voltage measured across the junction corresponds to what temperature, this simple device, called a "thermocouple," can measure the ambient temperature.

Thermoelectrics perform a similar feat using a nominally h.o.m.ogenous material, typically a semiconductor. If one end of the solid is hotter than the other, then the warmer side will have more electrons promoted from the full lower band up into the mostly empty conducting band than will be found at the cooler end. For some materials the holes that are generated in the nearly filled lower-energy orchestra will move much slower than the electrons in the higher-energy balcony, so we can focus only on the electrons. The electrons promoted at the hot side will diffuse over to the cooler end, where they will pile up, creating a voltage that repels any additional electrons from moving across the semiconductor. This voltage can then be used to run any device, acting as a battery does. To make an effective thermoelectric device, one wants a material that is a good conductor of electricity (so that the electrons can easily move across the solid) but a poor conductor of heat (so that the temperature difference can be maintained across the length of the solid). Research in developing materials well suited to thermoelectric applications is under way at many laboratories. Commercially viable devices could find application in, for example, hybrid automobiles, taking the waste heat from the engine and converting it into a voltage to charge the battery. In the world of the future, thanks to solid-state devices made possible through our understanding of quantum mechanics, the cars may not fly, but they may get much better mileage.

Another way to extract electrical power from random vibrations involves nanogenerators. These consist of special wires only several nanometers in diameter, composed of zinc oxide or other materials that are termed "piezoelectric." For these compounds a mechanical stress causes a slight shift in the crystal structure, which then generates a small voltage. Progress has been made in fabricating arrays of nanoscale wires of these piezoelectric materials. Any motion or vibration will cause the tiny filaments to flex and bend, thereby creating an electric voltage that can be used to provide power for another nanoscale machine or device.

Finally, we ask, can quantum mechanics do anything to develop small, lightweight batteries to power a personal jet pack? The answer may lie in the developing field of "nanotechnology." "Nano" comes from the Greek word for "dwarf," and a nanometer is one billionth of a meter-equivalent to approximately to the length of three atoms placed end to end. First let's see how normal batteries operate, and then I'll discuss why nanoengineering may lead to more powerful energy-storage devices.

In an automobile engine the electrical energy from the spark plug induces the chemical combustion of gasoline and oxygen. Batteries employ a reverse process, where chemical reactions are used to generate voltages.

In an electrolysis reaction, an electrical current pa.s.ses through reactants (often in liquid form) and provides the energy to initiate a chemical reaction. For example, one way to generate hydrogen gas (that does not involve the burning of fossil fuels) is to break apart water molecules. To do this we insert two electrodes in a beaker of water and attach them to an external electrical power supply, pa.s.sing a current through the fluid. One electrode will try to pull electrons out of the water (pure water is a very good electrical insulator), while the other will try to shove them in. The input of electrical energy overcomes the binding energy holding the water molecule together, and positively charged hydrogen ions (H+) are attracted to the electrode trying to give up electrons, while the negatively charged hydroxides (OH- units) move toward the electrode trying to accept electrons. The net result is that H2O molecules break into gaseous hydrogen and oxygen molecules.

In a battery, making use of essentially a reverse electrolysis process, different metals are employed for the electrodes (such as nickel and cadmium); they are chosen specifically because they undergo chemical reactions with certain liquids, leaving the reactant either positively or negatively charged. Where the metal electrode touches the chemical fluid (though batteries can also use a porous solid or a gel between the electrodes), electrical charges are either taken from the metal or added to it, depending on the chemical reaction that proceeds.76 A barrier is placed between the two electrodes, preventing the fluid from moving from one electrode to the other, so that negative charges (that is, electrons) pile up on one electrode and an absence of electrons (equivalent to an excess of positive charges) acc.u.mulates at the other.

The only way the excess electrons on one electrode, which are repelled from each other and would like to leave the electrode, can move to the positively charged electrode is if a wire is connected across the two terminals of the battery. The stored electrical charges can then flow through a circuit and provide the energy to operate a device. In an alkaline battery, once the chemical reactants in the fluid are exhausted, the device loses its ability to charge up the electrodes. Certain metal-fluid chemical reactions can proceed in one way when current is drawn from the battery, and in the reverse direction with the input of an electrical current (as in the water electrolysis example earlier), restoring the battery to its original state. Such batteries are said to be "rechargeable," and it is these structures that have exhibited the greatest increases in energy-storage capacity of late.

There have been great improvements in the energy content and storage capacity of rechargeable batteries, driven by the need for external power supplies in consumer electronics. In a battery the electrodes should be able to readily give up or accept electrons. Examination of the periodic table of the elements shows that lithium, similar in electronic structure to sodium and hydrogen, has one electron in an unpaired energy level (shown in Figure 31c) that it easily surrenders, leaving it positively charged. Batteries that make use of these lithium ions, with a lithium-cobalt-oxide electrode,77 and with the other electrode typically composed of carbon, produce nearly twice the open-circuit voltage of alkaline batteries. These batteries are lighter than those that use heavy metals as the electrodes, and a lithium-ion battery weighing eight ounces can generate more than 100,000 Joules of energy, compared to 50,000 Joules from a comparable-weight nickel-metal-hydride battery or 33,000 Joules from a half-pound lead-acid battery. These lightweight, high-energy-capacity, rechargeable batteries are consequently ideal for cell phones, iPods, and laptop computers.

As all the electrochemical action in a battery takes place when the electrolyte chemical comes onto physical contact with the electrode surface, the greater the surface area of the electrode, the more available sites for chemical reactions to proceed. One way to increase the surface area is to make the electrodes larger, but this conflicts with the desire for smaller and lighter electronic devices. Another way to increase the capacity of these batteries is to structure the electrodes differently. Nanotextured electrodes are essentially wrinkly on the atomic scale, dramatically increasing the surface area available for electrochemical reactions without a corresponding rise in electrode ma.s.s. Recent research on electrodes composed of silicon nanoscale wires finds that they are able to store ten times more lithium ions without appreciable swelling than carbon electrodes can. While not quite in the league of Iron Man's arc reactor, the ability to fabricate and manipulate materials on these nanometer-length scales is yielding batteries with properties worthy of the science fiction pulps.

This nanostructuring is also helping out with the laundry. Nanoscale filaments woven into textiles yield fabrics that are wrinkle resistant and repel staining. In addition to giving us whiter whites, nanotechnology is helping keep us healthy. A five-nanometer crystal contains only thirty-three hundred atoms, and such nanoparticles are excellent platforms for highly refined pharmaceutical delivery systems, able to provide, for example, chemotherapy drugs directly to cancerous cells while bypa.s.sing healthy cells.

We are only beginning to exploit the quantum mechanical advantages of nanostructured materials. There are ninety-two stable elements in the periodic table, and the specific details of the configuration of their electrons determines their physical, optical, and chemical properties. Crystalline silicon has a separation between its lowest filled states and first empty states of about one electron Volt, and if you want a semiconductor with a different energy gap, you must choose a different chemical element. Many technological applications would become possible, or would be improved, if the energy separation in crystalline silicon could be adjusted at will, without alloying with other chemicals that may have unintended deleterious effects on the material's properties. Recent research indicates that we can indeed make silicon a "tunable" semiconductor, provided we make it tiny.

Whether the energy separation between the filled orchestra and the empty balcony in our auditorium a.n.a.logy is one electron Volt (in the infrared portion of the spectrum), two electron Volts (red light), or ten electron Volts (ultraviolet light) is determined by the elements that make up the solid and the specific details of how each atom's quantum mechanical wave function overlaps and interacts with its neighbors. In large crystals, big enough to see with the naked eye or with an optical microscope, the electrons leaving one side of the solid will suffer many scattering collisions, so any influence from the walls of the crystal on the electron's wave function will have been washed out by the time the electron makes it to the other side. If the size of the solid is smaller than the extent of the electron's de Broglie wavelengths, then the electrons in the small crystal in essence are able to detect the size of the solid in which they reside. The smaller the "box" confining these electrons, the smaller the uncertainty in their location and-thanks to Heisenberg-the larger the uncertainty in their momentum. Consequently, "nanocrystals" can have an energy band gap that is determined primarily by the size of the solid and that we can control, freeing designers of solid-state devices from the "tyranny of chemistry."

The discoveries by a handful of physicists back in the 1920s and 1930s, explicating the rules that govern how atoms interact with light and each other, continue to shape and change the world we live in today and tomorrow.

AFTERWORD.

Journey into Mystery.

Every morning when I look out the window, I am reminded that we do not live in the world promised by science fiction pulp magazines, as I note in the skyline the absence of zeppelins. However, before I arise, the programmable solid-state timer on my coffee maker begins brewing my morning java. I thus literally do not get up in the morning without enjoying the benefits of a world informed by quantum mechanics.

As noted in the introduction, the pulps and science fiction comic books of fifty years ago certainly missed the mark (sometimes by a wide margin) in their prognostications of the technological innovations we would enjoy in the far-off future of the twenty-first century, a chronological milestone we have now reached. While their crystal b.a.l.l.s may have been foggy, these errors concerning technology seem presciently accurate compared to how far off their sociological predictions were. For example, few science fiction writers in the 1950s antic.i.p.ated how much public and private s.p.a.ce would be designated smoke-free, and it was generally expected that in the year 2000, as in the year 1950, a universal truth would remain that all scientists smoke pipes.

Predicting the evolution of language is another challenge for those trying to create visions of life in the distant future. It is amusing to read old Buck Rogers newspaper strips from 1929 on, and see, amid the descriptions of rockets ships, disintegration rays, and levitation belts, that colloquial expressions of early-twentieth-century 2 America remain vibrant and comprehensible in the twenty-fifth century. Buck, who fell asleep in the 1920s and awoke five hundred years later, can be excused for his use of slang, but apparently everyone in the future speaks this way. When facing an overwhelming robot army, warriors of a besieged city lament, "They've got us licked!" while another counsels, "Let's fade!" Gender equality appears set to move in reverse in the next five hundred years as well. Buck's fiancee leads a scouting team into enemy territory on Mars and gets separated from the rest of the group (cell phones appear to be a lost technology in the future). At the base ship Buck complains, "This is what comes of trusting a Woman with a Man's responsibility!" to which his lieutenant agrees, "They're all alike! They can drive a man crazy!" Just another reason why life as envisioned in science fiction isn't all it's cracked up to be.

Some of the writers of science fiction of fifty or more years ago had great optimism regarding the coming future. Those who were not proposing dystopian futures of atomic warfare and unceasing hostilities between nations (and alien species) were confident that many if not all of the ills that plague humankind would be defeated in the coming years thanks to . . . Science!

Science would free the housewife of the 1950s from the drudgery of housework and food preparation. The May 1949 issue of Science Ill.u.s.trated speculated that a "New Wiring Idea May Make the All-Electric House Come True." The wiring idea involved dropping the operating voltage from 110 volts to 24 volts, using a small transformer.78 The article argues that the benefit of using the lower voltage is that it enables the safe operation of many consumer items, and by adopting an "all-electric" household, the five-dollar cost of the transformer becomes a reasonable expense when amortized over a dozen household helpers. A photo spread shows that "a young housewife [...] from a single bedside panel with remote control switches [...] can turn on the percolator in the kitchen, turn radios on and off, light up a flood lamp in the yard for a late-home-coming husband [...] control the electric dishwasher and toaster [and] control every light and electrical outlet in and around a house from one single point." Little did the writer imagine that wireless technology, and semiconductor-based sensors whose operations could be preprogrammed, would remove the need for remote control switches on a bedside panel. No wonder social theorists worried about how the young housewife would fill the hours of the day in such a homemaker utopia.

Similarly, science has indeed revolutionized the workplace. Forget about inquiring, here in the twenty-first century, as to the location of our jet packs; what many want to know is: Where's our four-hour workday? It was a general expectation that by the year 2000, people would have so much leisure time that the pressing challenge would be to find ways to keep the populace entertained and occupied. Instead, for too many of us, the de facto workday has lengthened, thanks to the modern electronics that flowered from the development of quantum mechanics; the ability to be in constant contact has evolved into the necessity to be always connected.

Youngsters fifty years ago may not have been reading Modern Mechanics or Popular Science, but they learned of the brighter future to be delivered by scientific research and innovation in the pages of their comic books. While nowadays a best-selling comic book may have sales of a few hundred thousand copies, in 1960 sales of Superman comics were over eight hundred thousand per issue, and studies found that a single issue was shared and read by up to ten other kids. Lifelong att.i.tudes about better living through technology were fostered in the four-color pages of these ten-cent wonders.

The Man of Tomorrow, in particular, starred in many cla.s.sic stories describing the world of tomorrow. Superman was so popular in the 1940s and 1950s that at times he appeared in up to seven comics published by National Allied Periodicals (the company that would become DC Comics). In addition to his own stories in Action and Superman, the Man of Steel could be found in Lois Lane, Superman's Girlfriend; Jimmy Olsen, Superman's Pal; World's Finest (where he would team up every month with Batman and Robin); and Superboy and Adventure Comics (these latter two were filled with tales of Superman's teenage years as Superboy).

In 1958's Adventure Comics # 247, the Teen of Steel encounters three superpowered teenagers who, after playing some fairly harmless pranks on him, reveal to Superboy that they are from one thousand years in the future. These superteens have traveled back in time to offer Superboy membership in their club-the Legion of Superheroes. Apparently, one thousand years from now, a group of teenagers with a wide variety of powers and ability, from Earth and other planets, would band together to fight crime and evil throughout the United Planets. These young heroes were inspired by history tapes of the adventures of Superboy, and between their mastery of time travel and the Teen of Tomorrow's ability to fly so fast that he could "break the time barrier," Superboy would become a regular member of the Legion. Stories featuring the Legion would prove so popular with readers that they became a regular feature in Adventure and eventually squeezed Superboy out of the comic, aside from his appearances with the Legion in the thirtieth century.

According to these Legion tales, the promise of the s.p.a.ce program and the race to the moon under way in the 1960s would culminate, in the thirtieth century, in a society ruled by and dedicated to science! In the world of the Legion of Superheroes, if you found yourself in trouble, you didn't call the police; you sent for the science police!

While evil despots and warlike alien races would still bedevil humanity in the year 2958, the Legion of Superheroes tales featured a general sense of progress and hope that may have, in part, accounted for their popularity. A thousand years hence, intelligence and knowledge would be honored and rewarded. In Adventure # 321, when Lightning Lad, one of the Legion's founding members, was sentenced to life in prison for "betraying" the Legion by "revealing" the secret of the Concentrator,79 his cell featured b.u.t.tons that when pressed would provide the three basic necessities of life: food, water, and . . . books! The writers of the Legion of Superheroes stories promised that in the future, we would live in a golden age of science.

Similarly, over at Marvel Comics (though in the mid- to late 1950s the company was known as Atlas), scientists were also given pride of place in society. Stan Lee and Jack Kirby would not begin recounting the adventures of a quartet who took an ill-fated rocket trip "to the stars" and returned as the superpowered Fantastic Four until November 1961. Prior to this reintroduction of superheroes to the Marvel Comics universe in the 1960s, there were still plenty of menaces to be dealt with, as Tales to Astonish, Amazing Fantasy, Strange Tales, Journey into Mystery, and Tales of Suspense doc.u.mented the near continuous onslaught of monstrous invaders from s.p.a.ce, time, and other dimensions, all seeking global conquest. These would-be conquerors would regularly prove too much for local law enforcement and the military and often could be thwarted only by the lone efforts of a scientist!

And it's a good thing scientists were on the case, as Earth had to contend with the likes of Pildorr, Rorgg, Sporr, Orggo, Gruto, Rommbu, Bombu, Moomba, Dragoom, and Kraggoom. These creatures were rarely less than twenty feet tall and when not generic bug-eyed monsters or monstrously oversized bugs, they were composed of stone, smoke, fire, water, electricity, wood, mud, or "oozing paint." But none of these were as fearsome as Orgg, the Tax Collector from Outer s.p.a.ce!

Figure 51: Cover from Tales to Astonish # 13, describing the adventures of scientist Leslie Evans, who relates how "I Challenged Groot! The Monster from Planet X!" Such monstrous invaders from outer s.p.a.ce threatened our planet several times a month in pre-superhero Marvel Comics.

Fairly typical was the November 1960 issue of Tales to Astonish # 13 (Figure 51), where we hear the firsthand testimonial "I Challenged Groot! The Monster from Planet X!" This is presumably the same Planet X that is home to Goom (and his son Googam); the Thing from Planet X; and Kurrgo, the Master of Planet X.80 Groot was a giant treelike creature who came to Earth intending to steal an entire village and bring it back to his home planet for study. Bullets did not harm Groot, and his wooden hide was "too tough to burn." Groot's ability to mentally command other trees to move and do his bidding quickly disabled the town's defenses, and all seemed lost until the timely intervention of Leslie Evans, scientist. Working nonstop for several days, Evans developed the one weapon capable of immobilizing Groot-mutated termites. As shown in Figure 52, when the town's sheriff is chagrined that he "never even thought of that," a relieved villager points out, "That's why Evans is a scientist-and you're only a sheriff!" Meanwhile, Evans's wife hugs her husband, declaring, "Oh, darling, forgive me! I've been such a fool! I'll never complain about you again! Never!!" Personally, I can't tell you how many times I've heard those very same words from my own wife!81 While the scientist as world-saving hero is a caricature, I hope that I have convinced you that the scientist as world-changing hero is a pretty apt description for the physicists who developed the field of quantum mechanics. In this, these investigators followed a trail blazed hundreds of years ago. For science has always changed the future. Technological innovations, from movable type to steam engines to wireless radio to laptop computers, have time and again profoundly altered interactions among people, communities, and nations.

Discoveries in one field of science enable breakthroughs in oth- ers. The elucidation of the structure of DNA resulted from the interpretation of X-ray scattering data. This technique of X-ray spectroscopy was developed, through the application of quantum mechanics, to facilitate the study of crystalline structures by solid-state physicists. The deciphering of the human genome is inconceivable without the use of high-speed computers and data storage that rely on the transistor, invented over fifty years ago by scientists at Bell Labs. Using the tools developed by physicists in the last century, biologists in this century are poised to enact their own scientific revolution. Time will tell whether years from now another book will describe how "biologists changed the future." But one thing is for sure-we will not be able to embrace and partic.i.p.ate in that future without the discipline, curiosity, questioning, and reasoning that science requires. And if Orrgo the Unconquerable (Strange Tales # 90) ever returns, we'll be ready!

Figure 52: The final panel from Tales to Astonish # 13, showing Evans's reward for challenging Groot-the beginning of a "new, and better life" in which his wife "would never complain about [him] again!"

ACKNOWLEDGMENTS.

Sometimes, as the saying goes, the very best plan is to be lucky. I have been fortunate to have excellent professors when learning quantum mechanics, statistical mechanics and solid-state physics in college and graduate school. The first course I had in quantum physics was taught by Prof. Timothy Boyer, whose cla.s.sroom instruction provided an excellent foundation in the topic while his research in developing a non-quantum explanation for atomic behavior (involving cla.s.sical electrodynamics coupled with a zero-point radiation field) demonstrated that there was more than one way to view and account for natural phenomena. I am also happy to thank Herman c.u.mmins, Fred W. Smith, Kenneth Rubin, William Miller, Robert Alfano, Robert Sachs, Leo Kadanoff, h.e.l.lmut Fritzsche, Sidney Nagel, and Robert Street, who taught me, in the cla.s.sroom and out, about this fascinating field of physics and its many applications. My students at the University of Minnesota have been the inspiration and motivation for many of the examples presented here.

Writing a popular science book about quantum mechanics has been a challenging exercise, as it is very easy to trip up and misrepresent essential aspects of the theory in attempting to simplify the material for the non-expert. I am deeply grateful for the efforts of Benjamin Bayman, who read the entire ma.n.u.script in draft form and provided valuable feedback and corrections. In addition, William Zimmermann, E. Dan Dahlberg, Michel Janssen, Bruce Hammer, and Marco Peloso read portions of the text and I thank them for their insights and suggestions, along with the helpful comments of Yong-Zhong Qian, Paul Crowell, John Broadhurst, Allen Gold-man, and Roger Stuewer. I thank Bruce Hammer for the magnetic resonance image in Chapter 19. Any errors or confusing arguments that remain are solely my responsibility.

I am also grateful to Gotham Books in general, and my editor Patrick Mulligan in particular, for the opportunity to share with you the cool and practical field of quantum mechanics and its applications in nuclear and solid-state physics. Patrick's guidance during the writing and editing of this book has yielded a dramatically improved text, and his support from the very beginning in this book made it possible. The contributions of the copyeditor, Eileen Chetti, did much to improve the readability of the final ma.n.u.script. Michael Koelsch has done a wonderful job on the cover ill.u.s.tration and Elke Sigal on the book design. Christopher Jones did a fantastic job on the line drawings, beautifully ill.u.s.trating complex ideas throughout the book. Thanks also to Alex Schumann and Brian Andersson for the electron and laser diffraction photos, and the pencil-in-gla.s.s shot (with thanks to Eric Matthies for the Jon Osterman pencil). Some of the science fiction magazines cited here were procured from Kayo Books in San Francisco, California, a great resource for all things pulpy. Travers Johnson at Gotham and Jake Sugarman at William Morris Endeavor Entertainment were of great help throughout the difficult process of seeing the ma.n.u.script from rough first draft through to its final state. My agent, Jay Mandel, has always had my back, and his insights, advice and encouragement throughout this project have been crucial. He's been there from the start and every step of the way.

This book could not have been written without the limitless support and patience of my wife, Therese; and children, Thomas, Laura, and David, who graciously gave up their time with me while I was writing this book. I am grateful to Carolyn and Doug Kohrs for their friendship and support long before and throughout the writing of two books, and to Camille and Geoff Nash, who have always been there through thick and thin.

As I struggled with the early drafts of the ma.n.u.script, the editing advice, research and counsel of my son Thomas and wife, Therese, have been invaluable. I am proud and honored to thank them for their hard work and encouragement. I have been luckiest of all to benefit from my family's love and support. I know that the future will exceed the predictions of the sunniest, most optimistic science fiction, as long as I share it with them.

NOTES.

INTRODUCTION.

xi "well into the twenty-first century, we still await flying cars, jet packs": Follies of Science: 20th Century Visions of Our Fantastic Future, Eric Dregni and Jonathan Dregni (Speck Press, 2006).

xii "consider the long-term data storage accomplished by the Sumerians": Ancient Mesopotamia: Portrait of a Dead Civilization, A. Leo Oppenheim (University of Chicago Press, 1964); The Sumerians, C. Leonard Woolley (W. W. Norton and Co., 1965).

xii "In 1965 Gordon Moore noted": The Chip: How Two Americans Invented the Microchip and Launched a Revolution, T. R. Reid (Random House, 2001).

CHAPTER 1.

2 Amazing Stories: Cheap Thrills, The Amazing! Thrilling! Astounding! History of Pulp Fiction, Ron Goulart (Hermes, 2007).

3 "at the German Physical Society, Max Planck": Thirty Years That Shook Physics: The Story of Quantum Theory, George Gamow (Dover, 1985).

3 "Buck Rogers first appeared in the science fiction pulp Amazing Stories": Science Fiction of the 20th Century: An Ill.u.s.trated History, Frank M. Robinson (Collectors Press, 1999).

3 "or what publisher Hugo Gernsback called 'scientifiction'": Alternate Worlds: The Ill.u.s.trated History of Science Fiction, James Gunn (Prentice-Hall, 1975).

3 "Given the amazing pace of scientific progress": See, for example, The Victorian Internet: The Remarkable Story of the Telegraph and the Nineteenth Century's On-Line Pioneers, Tom Standage (Berkley Books, 1998); Electric Universe: How Electricity Switched on the Modern World, David Bodanis (Three Rivers Press, 2005).

4 "a revolution in physics occurred": Thirty Years That Shook Physics: The Story of Quantum Theory, George Gamow (Dover, 1985).

5 "'It is a great source of satisfaction to us'": "The Rise of Scientification," Hugo Gernsback, Amazing Stories Quarterly 1, 2 (Experimenter Publishing, Spring 1928).

6 "As Edward O. Wilson once cautioned": "The Drive to Discovery," Edward O. Wilson, American Scholar (Autumn 1984).

6 "Jules Verne considered the most extraordinary voyage of all": Paris in the Twentieth Century, Jules Verne (Random House, 1996).

9 "In one partic.i.p.ant's recollection, Bohr proposed a theoretical model": Thirty Years That Shook Physics: The Story of Quantum Theory, George Gamow (Dover, 1985).

11 "Faraday was the first to suggest that electric charges and magnetic materials": Electric Universe: How Electricity Switched on the Modern World, David Bodanis (Three Rivers Press, 2005).

CHAPTER 2.

13 "The Skylark of s.p.a.ce," Edward Elmer Smith, with Lee Hawkins Garby (uncredited) (The Buffalo Book Co., 1946); first serialized in Amazing Stories, 1928.