On Quantum Computing
As computer manufacturers move closer to the physical manufacturing limits imposed by nature, some new form of computing will need to be devised in order to continue the explosive growth that the computer industry is experiencing today. Indeed, if a new form is not devised, the current computing age will come to an abrupt halt. While a few unimplemented possibilities exist that will stretch today’s technology into the next century, scientists and computer engineers alike have feverishly begun to examine alternative methods to today’s silicon based computer systems. Currently, the leading alternative candidate, a conjugate of the two realms of quantum physics and computability, is what has been termed quantum computing.
To understand the need for alternative methods such as quantum computing, one must examine the modern history and development of computers. In the early portion of the 1900’s, when computing technology made the transition from mechanical gears to electromechanical units based on telephone relay systems, the major driving force behind technological advance was the United States government. This was primarily for code-breaking purposes (Clearwater 5-6).
As time passed, further advances were made, resulting in computers that were constructed with vacuum tubes. All of the advances resulted in faster computers, but the capabilities remained basically the same (Brooks 17). In fact, even today’s supercomputers are based on essentially the same design concepts as the earliest computers of the 1900’s, differing only in speed and memory (Brooks 15).
Noticing an emerging pattern with the increases in speed and memory, Gordon Moore, co-founder of Intel, proposed what has become “Moore’s Law” in the early 1970’s (Clearwater 7). Stating that the memory capacity of a chip doubles every eighteen months, Moore’s Law continues to hold today. During the almost thirty years since it was proclaimed, the number of transistors located on a computer chip has increased by a factor of one million, and at the same time, both the price and power consumption have been reduced by a factor of one-hundred-thousand (Milburn 158). However, the long-term viability of Moore’s Law has come into question recently. In October 1999, Paul Packan, a researcher at Intel’s labs, raised concerns that Intel may have reached the limit of its ability to miniaturize the microprocessor. Limited by nature’s maximum speed limit of the speed of light, engineers have compensated by squeezing more components together, shortening the distance the signals travel (Clearwater 7). This technique, however, has been stretched as far as it can, as Packan states that “There are currently no known solutions” to the problems they are facing (Yahoo News). Less than a month later, researchers Jack Hergenrother and Don Monroe at Lucent Technologies Bell Labs experienced a breakthrough. Claiming to be able to construct chips vertically rather than horizontally, they believe that many more transistors can be crammed onto a chip using this method. They also devised a method allowing for the potential doubling of processing power, by using two logic gates per transistor instead of one. Hergenrother and Monroe believe that this may be the breakthrough that would allow manufacturers to cross the “point one barrier.” (Wired News).
The “point-one barrier” is the point where engineers believe a shift must take place in the way computers are designed. This is the point where we reach the limits of today’s photographic etching process. At 0.1 microns in length, circuit patterns begin to blur, and the light used to etch the chips gets absorbed before it reaches the surface (Milburn 159). Also, it is at this point that the rules of the physical world cease to apply, as only a few atoms are need to construct the memory registers. At such small sizes, the rules of quantum mechanics take over. The Lucent breakthrough, however, looks to extend current methods into the next decade, but it is believed that by 2020, the laws of quantum physics will have to be adopted as the method of reading and writing bits (Clearwater 7-8).
Quantum physics arose at the turn of the 20th century as a result of the failure of classical physics to explain and predict the outcomes of experiments on both light and particles (Clearwater 49). The beginnings of quantum theory began in 1900, when Max Planck recognized the quantum nature of radiation, and in 1926, when Erwin Schrodinger provided a mathematical model of quantum mechanics (Brooks 5).
Using the principles established by Planck and Schrodinger, scientists started to examine the relationship of physics to computability in the mid 1970’s (Clearwater 45). In their book Explorations in Quantum Computing, Williams and Clearwater describe this relationship, stating
Essentially, the way information exists in computers today is easily translatable to storage in a quantum computer. Whether a computer uses today’s on and off switch mechanism or the quantum spin states, the fact remains that all that is needed is a method of distinguishing the values of one and zero.
With the passage of time, a greater understanding of quantum physics developed and the Nobel Prize-winning physicist Richard Feynman suggested the possibility of developing a computer based on quantum principles in 1982 (PC MAG). Envisioning a system that exploited these principles, Feynman saw a system that promised to offer much more than another incremental increase in processing power (Brooks 17). In fact, the newest theories involving quantum computing predict a time where quantum computers perform calculations exponentially faster than conventional computers. They also offer the promise of teleporting information, cracking unbreakable security codes, generating true random numbers, and communicating with correspondence that alerts authorized users to the presence of unauthorized trespassers (Clearwater 1).
These promising advantages of quantum computing are based on the notion that quantum methods of processing information are a radical departure from traditional classical methods. As a result of a quantum phenomenon, termed superposition, information can exist in undefined states and still maintain usability. In a quantum superposition, a bit of information can be both the values of zero and one simultaneously (Brooks 10). Consequently, quantum computing promises to offer entirely novel ways of computation with qualitatively new algorithms defined using the principles of quantum physics. At the same time, improvements in the speed, security, and quality of transferred information are possible (Brooks 4).
In theory, it is possible to construct a complete quantum computer. In November 1999, it was announced that scientists at MIT and the Los Alamos National Labs had developed the first quantum computer. While only capable of counting to four, this is held to be a significant advance. Such advances have led research team member David Cory to suggest a quantum equivalent to Moore’s Law. He states that “’in the last two years we’ve gone from two qubits to six qubits. This is a sixteenfold increase in power. We may have ten qubits in 2001, another sixteenfold increase’” (Groz 43).
Such power increases are not the only advantage of quantum computing. Quantum computers also offer an advantage in terms of energy efficiency. Theoretically, quantum computers are examples of reversible computers. Essentially, this feature of reversibility allows for the phenomenon of no net energy consumption. This is achieved because quantum computers have the ability to redeem expended input energy at the end of a computation (Clearwater 12).
Another advantage offered by quantum computers is the ability to perform the same calculations as a classical computer, but in less logical operations. The feature responsible for achieving this is the ability of a quantum computer to evaluate all possible inputs of an equation simultaneously (Clearwater 12).
However, even though complete marketable quantum computers are theoretically a possibility, there are problems that must be addressed in order for them to fulfill their promises and achieve their full potential (Clearwater 10). The largest of these problems is that at a quantum level, computers will be vulnerable to stray interactions with the environment in which the are placed (Clearwater 10). Compounding this issue is the fact that the environment may be affected by the quantum superpositions that exist within a quantum computer. There is a possibility that the quantum information will diffuse outside of the computer, spoiling storage and computation at the same time. It will become necessary to initiate some methods of stabilization to combat the effects of this process, decoherence (Brooks 23).
Currently, there are two proposed methods for combating the effects of decoherence. The first, proposed by David Deutsch in 1993, involves redundancy of data. Having multiple complete copies will reduce the chances of data loss, as data can be rebuilt from the backup copies (Brooks 23). The other method, independently proposed by both Peter Shor and Andrew Stearne in 1995, finds its roots in today’s Error Correction Code Random Access Memory (ECC RAM). Shor and Stearne’s ECC method of quantum computing involves a similar usage of error correction codes, whereby a single cubit is encoded by a string of qubits. Much like ECC RAM, if an error occurs, the original information can be rebuilt from the data stored within the single cubit (Brooks 24).
With an understanding of how to maintain data integrity, the first generation of quantum information technology is beginning to take shape. In fact, quantum-engineering solutions have been devised in the field of optical telecommunications (Brooks 33). In this field, classical bits of data (zero and one) are transmitted, amplified, and distributed using quantum mechanics. This hybrid is the first step toward the level of quantum computing that will arise in the second generation. In the second generation, quantum physics will be extended to the bits of information, resulting in information called qubits. Applications using these qubits will adhere to the principles of quantum superposition, and will be the realization of true quantum computing (Brooks 33).
Quantum computing applications for are already beginning to develop. Searching for at least one feasible application where an infant quantum computer could outperform a classical computer, Peter Shor discovered that a quantum computer could factor large integers highly efficiently. As David Deutsch discovered in his research, this is due to the ability of a quantum computer to examine all of the prime numbers at one time. The ability to factor large integers by a quantum computer is the key to breaking security methods such as the RSA-cryptosystem (Clearwater 113). Such an encryption scheme relies on the difficulty of factoring to create its security strength, as it is extremely difficult to factor a number such as 239812014798221 with today’s computers. However, with a quantum computer, this number can be factored with relative ease into its factors X and Y, simply by examining all prime numbers at once.
The ability to factor these prime numbers, or keys, could have a profound impact on secure transactions, effectively crippling today’s method of security. However, the laws of quantum mechanics seem to naturally provide a way to allow for the power of factorization and at the same time implement methods of security. In a world of quantum computers, the RSA-cryptosystem will no longer be needed. Quantum computers adhere to the Heisenberg Uncertainty Principle, which states that whenever and however a quantity is measure, “noise is added” to the measured quantity. This effectively alters the value of the measurement (Brooks 43). In the realm of quantum computing, this means that if an unauthorized eavesdropper taps into the quantum system to collect data, noise will be added to the data. This, in turn, can be easily detected by the authorized users, neutralizing the power of hacking techniques (Brooks 44). In other words, it is impossible to measure quantum systems without disturbing the data (Brooks 140). This ability is the result of a combination of the qubits’ natural superpositional state and the state of entanglement, where two or more quantum systems loose individuality by linking together to form one entity. Thus, disturbing the system is detectable throughout the entire system (Brooks 141).
With the capability of high-power number manipulation and its built-in security measures, quantum computing has the potential of becoming the successor of the immensely successful silicon microprocessor. If quantum computing is the heir apparent, many changes will take place in all facets of life. In terms of information technology, a new paradigm would be created in the ways information is processed. One can imagine a world where bank transactions are ultrasecure due to the natural security features of quantum entanglements and where computing speed will increase exponentially due to the ability to examine all inputs at one time, processing them in one operation. Instant access to information will also become a reality.
Such changes will also have a profound economic impact. For example, the advance could spark economic development across all types of industries. The power, speed, and security offered by quantum computers could be applied to many fields, from those who manufacture the technology to those who purchase it. However, many industries will need to make a huge shift in order to stay competitive. No longer will the status quo apply, because of the differences between the physical world and the quantum world. If the companies fall behind, the industries could experience an economic collapse due to the change to quantum computing. To avoid this, the entire industries may need to collaborate in creating the shift.
Education will have to shift as well. Institutions of learning will need to incorporate both quantum physics and quantum computing into the computer science curriculum. Fortunately, this has already begun to happen, as the University of Oxford, Caltech, and several other large universities have started teaching the theories behind quantum computing.
The advance toward quantum computing does pose a problem, however, for millions of computer scientists trained in what will be considered the “old way.” Years of education will abruptly no longer apply, as the shift to quantum computing is such a radical one. Many computer scientists may find themselves without a job until they complete their “re-education.”
A social division could also result from the change to quantum computing. Much like the division some believe to be taking place today with access to the Internet, a division could form between those who compute with quantum computers and those who do not. However, if the current trends in the computer industry can be used as a precedent, then perhaps a social division is not a tremendous problem as some might suggest. Initially, a division may take place, but the gap created would eventually shrink as time passes and prices fall.
The future looks bright, as quantum computing seems to offer an alternative way of computing. While not without its problems, quantum computers have the potential of changing the way information is processed. Indeed, such a development in the world of computers is needed, and with time, could solve the limitations being experienced today.
To understand the need for alternative methods such as quantum computing, one must examine the modern history and development of computers. In the early portion of the 1900’s, when computing technology made the transition from mechanical gears to electromechanical units based on telephone relay systems, the major driving force behind technological advance was the United States government. This was primarily for code-breaking purposes (Clearwater 5-6).
As time passed, further advances were made, resulting in computers that were constructed with vacuum tubes. All of the advances resulted in faster computers, but the capabilities remained basically the same (Brooks 17). In fact, even today’s supercomputers are based on essentially the same design concepts as the earliest computers of the 1900’s, differing only in speed and memory (Brooks 15).
Noticing an emerging pattern with the increases in speed and memory, Gordon Moore, co-founder of Intel, proposed what has become “Moore’s Law” in the early 1970’s (Clearwater 7). Stating that the memory capacity of a chip doubles every eighteen months, Moore’s Law continues to hold today. During the almost thirty years since it was proclaimed, the number of transistors located on a computer chip has increased by a factor of one million, and at the same time, both the price and power consumption have been reduced by a factor of one-hundred-thousand (Milburn 158). However, the long-term viability of Moore’s Law has come into question recently. In October 1999, Paul Packan, a researcher at Intel’s labs, raised concerns that Intel may have reached the limit of its ability to miniaturize the microprocessor. Limited by nature’s maximum speed limit of the speed of light, engineers have compensated by squeezing more components together, shortening the distance the signals travel (Clearwater 7). This technique, however, has been stretched as far as it can, as Packan states that “There are currently no known solutions” to the problems they are facing (Yahoo News). Less than a month later, researchers Jack Hergenrother and Don Monroe at Lucent Technologies Bell Labs experienced a breakthrough. Claiming to be able to construct chips vertically rather than horizontally, they believe that many more transistors can be crammed onto a chip using this method. They also devised a method allowing for the potential doubling of processing power, by using two logic gates per transistor instead of one. Hergenrother and Monroe believe that this may be the breakthrough that would allow manufacturers to cross the “point one barrier.” (Wired News).
The “point-one barrier” is the point where engineers believe a shift must take place in the way computers are designed. This is the point where we reach the limits of today’s photographic etching process. At 0.1 microns in length, circuit patterns begin to blur, and the light used to etch the chips gets absorbed before it reaches the surface (Milburn 159). Also, it is at this point that the rules of the physical world cease to apply, as only a few atoms are need to construct the memory registers. At such small sizes, the rules of quantum mechanics take over. The Lucent breakthrough, however, looks to extend current methods into the next decade, but it is believed that by 2020, the laws of quantum physics will have to be adopted as the method of reading and writing bits (Clearwater 7-8).
Quantum physics arose at the turn of the 20th century as a result of the failure of classical physics to explain and predict the outcomes of experiments on both light and particles (Clearwater 49). The beginnings of quantum theory began in 1900, when Max Planck recognized the quantum nature of radiation, and in 1926, when Erwin Schrodinger provided a mathematical model of quantum mechanics (Brooks 5).
Using the principles established by Planck and Schrodinger, scientists started to examine the relationship of physics to computability in the mid 1970’s (Clearwater 45). In their book Explorations in Quantum Computing, Williams and Clearwater describe this relationship, stating
There are a number of properties that quantum systems possess that lend themselves to computational applications. For example, at the quantum level, the values of certain observable quantities are restricted to a finite set of possibilities. The significance of this is that, in any computer, each bit must be stored in the state of some physical system. In a quantum computer, each bit could be represented by the state of a simple 2-state quantum system such as the spin state of spin-1/2 particle. As the spin of a particle is quantized, we can use one spin state to represent the binary value 0, and the other state to represent the binary value 1. Any 2-state quantum system, such as the direction of the polarization of a photon, or the discrete energy levels in an excited atom would work equally well. Once you have a way of encoding the binary values 0 and 1 in the states of a physical system, you can envisage making a complete memory register out of a chain of such systems (50).
Essentially, the way information exists in computers today is easily translatable to storage in a quantum computer. Whether a computer uses today’s on and off switch mechanism or the quantum spin states, the fact remains that all that is needed is a method of distinguishing the values of one and zero.
With the passage of time, a greater understanding of quantum physics developed and the Nobel Prize-winning physicist Richard Feynman suggested the possibility of developing a computer based on quantum principles in 1982 (PC MAG). Envisioning a system that exploited these principles, Feynman saw a system that promised to offer much more than another incremental increase in processing power (Brooks 17). In fact, the newest theories involving quantum computing predict a time where quantum computers perform calculations exponentially faster than conventional computers. They also offer the promise of teleporting information, cracking unbreakable security codes, generating true random numbers, and communicating with correspondence that alerts authorized users to the presence of unauthorized trespassers (Clearwater 1).
These promising advantages of quantum computing are based on the notion that quantum methods of processing information are a radical departure from traditional classical methods. As a result of a quantum phenomenon, termed superposition, information can exist in undefined states and still maintain usability. In a quantum superposition, a bit of information can be both the values of zero and one simultaneously (Brooks 10). Consequently, quantum computing promises to offer entirely novel ways of computation with qualitatively new algorithms defined using the principles of quantum physics. At the same time, improvements in the speed, security, and quality of transferred information are possible (Brooks 4).
In theory, it is possible to construct a complete quantum computer. In November 1999, it was announced that scientists at MIT and the Los Alamos National Labs had developed the first quantum computer. While only capable of counting to four, this is held to be a significant advance. Such advances have led research team member David Cory to suggest a quantum equivalent to Moore’s Law. He states that “’in the last two years we’ve gone from two qubits to six qubits. This is a sixteenfold increase in power. We may have ten qubits in 2001, another sixteenfold increase’” (Groz 43).
Such power increases are not the only advantage of quantum computing. Quantum computers also offer an advantage in terms of energy efficiency. Theoretically, quantum computers are examples of reversible computers. Essentially, this feature of reversibility allows for the phenomenon of no net energy consumption. This is achieved because quantum computers have the ability to redeem expended input energy at the end of a computation (Clearwater 12).
Another advantage offered by quantum computers is the ability to perform the same calculations as a classical computer, but in less logical operations. The feature responsible for achieving this is the ability of a quantum computer to evaluate all possible inputs of an equation simultaneously (Clearwater 12).
However, even though complete marketable quantum computers are theoretically a possibility, there are problems that must be addressed in order for them to fulfill their promises and achieve their full potential (Clearwater 10). The largest of these problems is that at a quantum level, computers will be vulnerable to stray interactions with the environment in which the are placed (Clearwater 10). Compounding this issue is the fact that the environment may be affected by the quantum superpositions that exist within a quantum computer. There is a possibility that the quantum information will diffuse outside of the computer, spoiling storage and computation at the same time. It will become necessary to initiate some methods of stabilization to combat the effects of this process, decoherence (Brooks 23).
Currently, there are two proposed methods for combating the effects of decoherence. The first, proposed by David Deutsch in 1993, involves redundancy of data. Having multiple complete copies will reduce the chances of data loss, as data can be rebuilt from the backup copies (Brooks 23). The other method, independently proposed by both Peter Shor and Andrew Stearne in 1995, finds its roots in today’s Error Correction Code Random Access Memory (ECC RAM). Shor and Stearne’s ECC method of quantum computing involves a similar usage of error correction codes, whereby a single cubit is encoded by a string of qubits. Much like ECC RAM, if an error occurs, the original information can be rebuilt from the data stored within the single cubit (Brooks 24).
With an understanding of how to maintain data integrity, the first generation of quantum information technology is beginning to take shape. In fact, quantum-engineering solutions have been devised in the field of optical telecommunications (Brooks 33). In this field, classical bits of data (zero and one) are transmitted, amplified, and distributed using quantum mechanics. This hybrid is the first step toward the level of quantum computing that will arise in the second generation. In the second generation, quantum physics will be extended to the bits of information, resulting in information called qubits. Applications using these qubits will adhere to the principles of quantum superposition, and will be the realization of true quantum computing (Brooks 33).
Quantum computing applications for are already beginning to develop. Searching for at least one feasible application where an infant quantum computer could outperform a classical computer, Peter Shor discovered that a quantum computer could factor large integers highly efficiently. As David Deutsch discovered in his research, this is due to the ability of a quantum computer to examine all of the prime numbers at one time. The ability to factor large integers by a quantum computer is the key to breaking security methods such as the RSA-cryptosystem (Clearwater 113). Such an encryption scheme relies on the difficulty of factoring to create its security strength, as it is extremely difficult to factor a number such as 239812014798221 with today’s computers. However, with a quantum computer, this number can be factored with relative ease into its factors X and Y, simply by examining all prime numbers at once.
The ability to factor these prime numbers, or keys, could have a profound impact on secure transactions, effectively crippling today’s method of security. However, the laws of quantum mechanics seem to naturally provide a way to allow for the power of factorization and at the same time implement methods of security. In a world of quantum computers, the RSA-cryptosystem will no longer be needed. Quantum computers adhere to the Heisenberg Uncertainty Principle, which states that whenever and however a quantity is measure, “noise is added” to the measured quantity. This effectively alters the value of the measurement (Brooks 43). In the realm of quantum computing, this means that if an unauthorized eavesdropper taps into the quantum system to collect data, noise will be added to the data. This, in turn, can be easily detected by the authorized users, neutralizing the power of hacking techniques (Brooks 44). In other words, it is impossible to measure quantum systems without disturbing the data (Brooks 140). This ability is the result of a combination of the qubits’ natural superpositional state and the state of entanglement, where two or more quantum systems loose individuality by linking together to form one entity. Thus, disturbing the system is detectable throughout the entire system (Brooks 141).
With the capability of high-power number manipulation and its built-in security measures, quantum computing has the potential of becoming the successor of the immensely successful silicon microprocessor. If quantum computing is the heir apparent, many changes will take place in all facets of life. In terms of information technology, a new paradigm would be created in the ways information is processed. One can imagine a world where bank transactions are ultrasecure due to the natural security features of quantum entanglements and where computing speed will increase exponentially due to the ability to examine all inputs at one time, processing them in one operation. Instant access to information will also become a reality.
Such changes will also have a profound economic impact. For example, the advance could spark economic development across all types of industries. The power, speed, and security offered by quantum computers could be applied to many fields, from those who manufacture the technology to those who purchase it. However, many industries will need to make a huge shift in order to stay competitive. No longer will the status quo apply, because of the differences between the physical world and the quantum world. If the companies fall behind, the industries could experience an economic collapse due to the change to quantum computing. To avoid this, the entire industries may need to collaborate in creating the shift.
Education will have to shift as well. Institutions of learning will need to incorporate both quantum physics and quantum computing into the computer science curriculum. Fortunately, this has already begun to happen, as the University of Oxford, Caltech, and several other large universities have started teaching the theories behind quantum computing.
The advance toward quantum computing does pose a problem, however, for millions of computer scientists trained in what will be considered the “old way.” Years of education will abruptly no longer apply, as the shift to quantum computing is such a radical one. Many computer scientists may find themselves without a job until they complete their “re-education.”
A social division could also result from the change to quantum computing. Much like the division some believe to be taking place today with access to the Internet, a division could form between those who compute with quantum computers and those who do not. However, if the current trends in the computer industry can be used as a precedent, then perhaps a social division is not a tremendous problem as some might suggest. Initially, a division may take place, but the gap created would eventually shrink as time passes and prices fall.
The future looks bright, as quantum computing seems to offer an alternative way of computing. While not without its problems, quantum computers have the potential of changing the way information is processed. Indeed, such a development in the world of computers is needed, and with time, could solve the limitations being experienced today.
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