Physics of the Impossible by Michio Kaku
Here’s how Bradley and company’s teleportation device works. First they start with a collection of supercold rubidium atoms in a BEC state. They then apply a beam of matter to the BEC (also made of rubidium atoms). These atoms in the beam also want to tumble down to the lowest energy state, so they shed their excess energy in the form of a pulse of light. This light beam is then sent down a fiber-optic cable. Remarkably the light beam contains all the quantum information necessary to describe the original matter beam (e.g., the location and velocity of all its atoms). Then the light beam hits another BEC, which then converts the light beam into the original matter beam.
This new teleportation method has tremendous promise, since it doesn’t involve the entanglement of atoms. But this method also has its problems. It depends crucially on the properties of BECs, which are difficult to create in the laboratory. Furthermore, the properties of BECs are quite peculiar, because they behave as if they were one gigantic atom. In principle, bizarre quantum effects that we see only at the atomic level can be seen with the naked eye with a BEC. This was once thought to be impossible.
The immediate practical application of BECs is to create “atomic lasers.” Lasers, of course, are based on coherent beams of photons vibrating in unison. But a BEC is a collection of atoms vibrating in unison, so it’s possible to create beams of BEC atoms that are all coherent. In other words, a BEC can create the counterpart of the laser, the atomic laser or matter laser, which is made of BEC atoms. The commercial applications of lasers are enormous, and the commercial applications of atomic lasers could also be just as profound. But because BECs exist only at temperatures hovering just above absolute zero, progress in this field will be slow, albeit steady.
Given the progress we have made, when might we be able to teleport ourselves? Physicists hope to teleport complex molecules in the coming years. After that perhaps a DNA molecule or even a virus may be teleported within decades. There is nothing in principle to prevent teleporting an actual person, just as in the science fiction movies, but the technical problems facing such a feat are truly staggering. It takes some of the finest physics laboratories in the world just to create coherence between tiny photons of light and individual atoms. Creating quantum coherence involving truly macroscopic objects, such as a person, is out of the question for a long time to come. In fact, it will likely take many centuries, or longer, before everyday objects could be teleported—if it’s possible at all.
QUANTUM COMPUTERS
Ultimately, the fate of quantum teleportation is intimately linked to the fate of the development of quantum computers. Both use the same quantum physics and the same technology, so there is intense cross-fertilization between these two fields. Quantum computers may one day replace the familiar digital computer sitting on our desks. In fact, the future of the world’s economy may one day depend on such computers, so there is enormous commercial interest in these technologies. One day Silicon Valley could become a Rust Belt, replaced by new technologies emerging from quantum computing.
Ordinary computers compute on a binary system of 0s and 1s, called bits. But quantum computers are far more powerful. They can compute on qubits, which can take values between 0 and 1. Think of an atom placed in a magnetic field. It is spinning like a top, so its spin axis can point either up or down. Common sense tells us that the spin of the atom can be either up or down but not both at the same time. But in the strange world of the quantum, the atom is described as the sum of two states, the sum of an atom spinning up and an atom spinning down. In the netherworld of the quantum, every object is described by the sum of all possible states. (If large objects, like cats, are described in this quantum fashion, it means that you have to add the wave function of a live cat to that of a dead cat, so the cat is neither dead nor alive, as I will discuss in greater detail in Chapter 13.)
Now imagine a string of atoms aligned in a magnetic field, with the spin aligned in one fashion. If a laser beam is shone on this string of atoms the laser beam will bounce off this collection of atoms, flipping the spin axis of some of the atoms. By measuring the difference between the incoming and outgoing laser beam, we have accomplished a complicated quantum “calculation,” involving the flipping of many spins.
Quantum computers are still in their infancy. The world’s record for a quantum computation is 3 × 5 = 15, hardly a calculation that will supplant today’s supercomputers. Quantum teleportation and quantum computers both share the same fatal weakness: maintaining coherence for large collections of atoms. If this problem can be solved, it would be an enormous breakthrough in both fields.
The CIA and other secret organizations are intensely interested in quantum computers. Many of the world’s secret codes depend on a “key,” which is a very large integer, and one’s ability to factor it into prime numbers. If the key is the product of two numbers, each with one hundred digits, then it might take a digital computer more than a hundred years to find these two factors from scratch. Such a code is essentially unbreakable today.
But in 1994 Peter Shor of Bell Labs showed that factoring large numbers could be child’s play for a quantum computer. This discovery immediately piqued the interest of the intelligence community. In principle a quantum computer could break all the world’s codes, throwing the security of today’s computer systems into total disorder. The first country that is able to build such a system would be able to unlock the deepest secrets of other nations and organizations.
Some scientists have speculated that in the future the world’s economy might depend on quantum computers. Silicon-based digital computers are expected to reach their physical limits in terms of increased computer power sometime after 2020. A new, more powerful family of computers might be necessary if technology is going to continue to advance. Others are exploring the possibility of reproducing the power of the human brain via quantum computers.
The stakes, therefore, are very high. If we can solve the problem of coherence, not only might we be able to solve the challenge of teleportation; we might also have the ability to advance technology of all kinds in untold ways via quantum computers. This breakthrough is so important that I will return to this discussion in later chapters.
As I pointed out earlier, coherence is extraordinarily difficult to maintain in the lab. The tiniest vibration could upset the coherence of two atoms and destroy the computation. Today it is very difficult to maintain coherence in more than just a handful of atoms. Atoms that are originally in phase begin to decohere within a matter of nanoseconds to, at best, a second. Teleportation must be done very rapidly, before the atoms begin to decohere, thus placing another restriction on quantum computation and teleportation.
In spite of these challenges, David Deutsch of Oxford University believes that these problems can be overcome: “With luck, and with the help of recent theoretical advances, [a quantum computer] may take a lot less than 50 years…. It would be an entirely new way of harnessing nature.”
To build a useful quantum computer we would need to have hundreds to millions of atoms vibrating in unison, an achievement far beyond our capabilities today. Teleporting Captain Kirk would be astronomically difficult. We would have to create a quantum entanglement with a twin of Captain Kirk. Even with nanotechnology and advanced computers, it is difficult to see how this could be accomplished.
So teleportation exists at the atomic level, and we may eventually teleport complex and even organic molecules within a few decades. But the teleportation of a macroscopic object will have to wait for several decades to centuries beyond that, or longer, if indeed it is even possible. Therefore teleporting complex molecules, perhaps even a virus or a living cell, qualifies as a Class I impossibility, one that should be possible within this century. But teleporting a human being, although it is allowed by the laws of physics, may take many centuries beyond that, assuming it is possible at all. Hence I would qualify that kind of teleportation as a Class II impossibility.
5: TELEPATHY
If you haven’t foun
—JOHN WHEELER
Only those who attempt the absurd will achieve the impossible.
—M. C. ESCHER
A. E. van Vogt’s novel Slan captures the vast potential and our darkest fears associated with the power of telepathy.
Jommy Cross, the protagonist in the novel, is a “slan,” a dying race of superintelligent telepaths.
His parents were brutally murdered by enraged mobs of humans, who fear and despise all telepaths, because of the enormous power wielded by those who can intrude on their private, most intimate thoughts. Humans mercilessly hunt down the slans like animals. With their characteristic tendrils growing out of their heads, slans are easy to spot. In the course of the book, Jommy tries to make contact with other slans who might have fled into outer space to escape the witch hunts of humans determined to exterminate them.
Historically, mind reading has been seen as so important that it has often been associated with the gods. One of the most fundamental powers of any god is the ability to read our minds and hence answer our deepest prayers. A true telepath who could read minds at will could easily become the wealthiest, most powerful person on Earth, able to enter into the minds of Wall Street bankers or to blackmail and coerce his rivals. He would pose a threat to the security of governments. He could effortlessly steal a nation’s most sensitive secrets. Like the slans, he would be feared and perhaps hunted down.
The enormous power of a true telepath was highlighted in the landmark Foundation series by Isaac Asimov, often touted as one of the greatest science fiction epics of all time. A Galactic Empire that has ruled for thousands of years is on the verge of collapse and ruin. A secret society of scientists, called the Second Foundation, uses complex equations to predict that the Empire will eventually fall and plunge civilization into thirty thousand years of darkness. The scientists draft an elaborate plan based on their equations in an effort to reduce this collapse of civilization down to just a few thousand years. But then disaster strikes. Their elaborate equations fail to predict a single event, the birth of a mutant called the Mule, who is capable of controlling minds over great distances and hence able to seize control of the Galactic Empire. The galaxy is doomed to thirty thousand years of chaos and anarchy unless this telepath can be stopped.
Although science fiction is full of fantastic tales concerning telepaths, the reality is much more mundane. Because thoughts are private and invisible, for centuries charlatans and swindlers have taken advantage of the naïve and gullible among us. One simple parlor trick used by magicians and mentalists is to use a shill—an accomplice planted in the audience whose mind is then “read” by the mentalist.
The careers of several magicians and mentalists, in fact, have been based on the famous “hat trick,” in which people write private messages on strips of paper, which are then placed in a hat. The magician then proceeds to tell the audience what is written on each strip of paper, amazing everyone. There is a deceptively simple explanation for this ingenious trick (see the notes).
One of the most famous cases of telepathy did not involve a shill but an animal, Clever Hans, a wonder horse that astonished European audiences in the 1890s. Clever Hans, to the amazement of audiences, could perform complex mathematical feats of calculation. If, for example, you asked Clever Hans to divide 48 by 6, the horse would beat its hoof 8 times. Clever Hans, in fact, could divide, multiply, add fractions, spell, and even identify musical tones. Clever Hans’s fans declared that he was either more intelligent than many humans, or he could telepathically pick people’s brains.
But Clever Hans was not the product of some clever trickery. The marvelous ability of Clever Hans to perform arithmetic even fooled his trainer. In 1904 prominent psychologist Professor C. Strumpf was brought in to analyze the horse and could find no obvious evidence of trickery or covert signaling to the horse, only adding to the public’s fascination with Clever Hans. Three years later, however, Strumpf’s student, psychologist Oskar Pfungst, did much more rigorous testing and finally discovered Clever Hans’s secret. All he really did was observe the subtle facial expressions of his trainer. The horse would continue to beat his hoofs until his trainer’s facial expression changed slightly, at which point he would stop beating. Clever Hans could not read people’s minds or perform arithmetic; he was simply a shrewd observer of people’s faces.
There have been other “telepathic” animals in recorded history. As early as 1591 a horse named Morocco became famous in England and made a fortune for his owner by picking out people in the audience, pointing out letters of the alphabet, and adding the total of a pair of dice. He caused such a sensation in England that Shakespeare immortalized him in his play Love’s Labour’s Lost as “the dancing horse.”
Gamblers also are able to read people’s minds in a limited sense. When a person sees something pleasurable, the pupils of his eyes usually dilate. When he sees something undesirable (or performs a mathematical calculation), his pupils contract. Gamblers can read the emotions of their poker-faced opponents by looking for their eyes to dilate or contract. This is one reason that gamblers often wear colored visors over their eyes, to shield their pupils. One can also bounce a laser beam off a person’s pupil and analyze where it is reflected, and thereby determine precisely where a person is looking. By analyzing the motion of the reflected dot of laser light, one can determine how a person scans a picture. By combining these two technologies, one can then determine a person’s emotional reaction as he scans a picture, all without his permission.
PSYCHICAL RESEARCH
The first scientific studies of telepathy and other paranormal phenomenon were conducted by the Society for Psychical Research, founded in London in 1882. (The term “mental telepathy” was coined that year by F. W. Myers, an associate of the society.) Past presidents of this society included some of the most notable figures of the nineteenth century. The society, which still exists today, was able to debunk the claims of many frauds, but was often split between the spiritualists, who firmly believed in the paranormal, and the scientists, who wanted more serious scientific study.
One researcher connected with the society, Dr. Joseph Banks Rhine, began the first systematic and rigorous study of psychic phenomena in the United States in 1927, founding the Rhine Institute (now called the Rhine Research Center) at Duke University, North Carolina. For decades he and his wife, Louisa, conducted some of the first scientifically controlled experiments in the United States on a wide variety of parapsychological phenomena and published them in peer-reviewed publications. It was Rhine who coined the term “extrasensory perception” (ESP) in one of his first books.
Rhine’s laboratory, in fact, set the standard for psychic research. One of his associates, Dr. Karl Zener, developed the five-symbol card system, now known as Zener cards, for analyzing telepathic powers. The vast majority of results showed absolutely no evidence of telepathy. But a small minority of experiments seemed to show small but remarkable correlations in the data that could not be explained by pure chance. The problem was that these experiments often could not be duplicated by other researchers.
Although Rhine tried to establish a reputation for rigor, his reputation was somewhat tarnished by an encounter with a horse called Lady Wonder. This horse could perform dazzling feats of telepathy, such as knocking over toy alphabet blocks and thereby spelling out words that members of an audience were thinking. Rhine apparently did not know about the Clever Hans effect. In 1927 Rhine analyzed Lady Wonder in some detail and concluded, “There is left then, only the telepathic explanation, the transference of mental influence by an unknown process. Nothing was discovered that failed to accord with it, and no other hypothesis proposed seems tenable in view of the results.” Later, Milbourne Christopher revealed the true source of Lady Wonder’s telepathic power: subtle motions of the whip carried by the horse’s owner. The subtle movements of the whip were cues for Lady Wonder to stop beating her hoof. (But ev
Rhine’s reputation suffered a final crushing blow, however, when he was on the verge of retiring. He was seeking a successor with an untarnished reputation to carry on the work of his institute. One promising candidate was Dr. Walter Levy, whom he hired in 1973. Dr. Levy was a rising star in the field, reporting sensational study results seeming to demonstrate that mice could telepathically alter a computer’s random number generator. However, suspicious lab workers discovered that Dr. Levy was surreptitiously sneaking into the lab at night to alter the results of the tests. He was caught red-handed doctoring the data. Further tests showed that the mice possessed no telepathic power whatsoever, and Dr. Levy was forced to resign from the institute in disgrace.
TELEPATHY AND STAR GATE
Interest in the paranormal took a deadly turn at the height of the cold war, during which a number of clandestine experiments on telepathy, mind control, and remote viewing were spawned. (Remote viewing is “seeing” a distant location by the mind alone, by reading the minds of others.) Star Gate was the code name for a number of secret CIA-sponsored studies (such as Sun Streak, Grill Flame, and Center Lane). The efforts got their start around 1970 when the CIA concluded that the Soviet Union was spending up to 60 million rubles a year on “psychotronic” research. There was concern that the Soviets might be using ESP to locate U.S. submarines and military installations, to identify spies, and to read secret papers.