Quantum Computers? The Future?

[planetaryhamsterwheel]

This is a pretty interesting essay and was looking for comments about it.
Do you guys think quantum computers are the future?
In cryptography, what do you think will have to change to ensure privacy?

Title: Shift Happens

Conceptualize a modern computer. What is probably seen is a mental image of a thin and portable laptop, like a MacBook Air, or a bulky and robust desktop, like a Voodoo Omen. However the configuration, what is not seen is the representation and evolvement of years of sophisticated advancements starting with the early ideas of electrical engineers like Charles Babbage. Charles Babbage (1791-1871) founded the modern analytic computer through his research and development of the “principles of the analytic engine, the forerunner of the modern electronic computer” (Castells 93). From his ideas sprouted the immanent computer, capable of storing and processing data. The object previously visualized looks nothing like its forerunners.

The first computers developed in the 20th century were large and weighed over 30 tons. Now, the average weight of the computer is 99.99% less than their earlier counterparts. Essentially, all computers operate on the same basic concepts; they use semiconductors, capacitors, and transistors to manipulate data from binary bits to human-readable form. Technology is changing at a frantic pace. As seen with modern computers, as they continue to grow smaller and more efficient, there will be a time when they can shrink no more and the exponential advancements in computer technology will start to level out.

According to Moore’s Law, “the power of microprocessor technology doubles and its costs of production fall in half every 18 months” (Elert). The speed of microprocessors is almost directly proportional to the size and number of integrated circuits on a single die, or silicon chip. Already, chip manufacturers are proud to claim record numbers of transistors on CPUs (central processing units). One example would be Tukwila, boasting a record of 2 billion transistors. The process of miniaturizing circuits is based off of decreasing the microns, or the width of the smallest wires on the chip. Currently, 32nm (nanometer) chips are hitting mainstream computers and plans for even smaller designs are being formulated. Keep in mind, “the diameter of an atom ranges from about 0.1 to 0.5 nanometers” (Weaver 569). If technology continues in accordance to Moore’s law, the progression of smaller processors will be limited by the size of individual atoms. Once this point is reached, the laws of physics intervene. Intel, a leader in silicon photonics, explained to the scientific community in November of 2007 “that it will continue to adhere to Moore’s law at least through the end of the decade” (Otellini). Even Intel admits that it will soon run into a stumbling block in the near future. To compensate for the limitations in modern computers, quantum computers are making their debut and are beginning to change computer technology as a whole. In order to understand the superiority of quantum computers have over typical silicon-based computers, an excavation into the fundamental workings, the potential power, and the societal impact of quantum computers will be conducted.

In a quantum computer, the fundamental unit of information (called a quantum bit or qubit), is not binary but rather more quaternary in nature. This qubit property arises as a direct consequence of its adherence to the laws of quantum mechanics which differ radically from the laws of classical physics. A qubit can exist not only in a state corresponding to the logical state 0 or 1 as in a classical bit, but also in states corresponding to a blend or superposition of these classical states. In other words, a qubit can exist as a zero, a one, or simultaneously as both 0 and 1, with a numerical coefficient representing the probability for each state. This may seem counterintuitive, since everyday phenomenon are governed by classical physics, not quantum mechanics -- which takes over at the atomic level.

In a traditional computer, information is encoded in a series of bits. These bits are manipulated via Boolean logic gates arranged in succession to produce an end result. Similarly, a quantum computer manipulates qubits by “executing a series of quantum gates, each yielding a unitary transformation acting on a single qubit or pair of qubits” (Grosz 21). In applying these gates in succession, a quantum computer can perform a complicated unitary transformation to a set of qubits in some initial state. The qubits can then be measured, with this measurement serving as the final computational result. This similarity in calculation methods between a classical and quantum computer presents that in theory, a classical computer can accurately simulate a quantum computer. In other words, a classical computer would be able to do anything a quantum computer can. So why bother with quantum computers? Although a classical computer can theoretically simulate a quantum computer, it is incredibly inefficient, so much so that a classical computer is effectively incapable of performing many tasks that a quantum computer could perform with ease. The simulation of a quantum computer on a classical one is a “computationally hard problem because the correlations among quantum bits are qualitatively different from correlations among classical bits” (Brown 103), as first explained by John Bell. Take for example a system of only a few hundred qubits, this exists in a Hilbert space of dimension ~1090 that in simulation would require a classical computer to work with exponentially large matrices (to perform calculations on each individual state, which is also represented as a matrix), meaning it would take an exponentially longer time than even a primitive quantum computer.

Richard Feynman was among the first to recognize the potential in quantum superposition for solving such problems much much faster. For example, a system of 500 qubits, which is impossible to simulate classically, represents a quantum superposition of as many as 2500 states. Each state would be classically equivalent to a single list of 500 1's and 0's. Any quantum operation on that system --a particular pulse of radio waves, for instance, whose action might be to execute a controlled-NOT operation on the 100th and 101st qubits-- would simultaneously operate on all 2500 states. Hence with one fell swoop, one tick of the computer clock, a quantum operation could compute not just on one machine state, as serial computers do, but on 2500 machine states at once! Unfortnately, observing the system would cause it to collapse into a single quantum state corresponding to a single answer, a single list of 500 1's and 0's, as dictated by the measurement axiom of quantum mechanics. This is an exciting result because, this answer, derived from the massive quantum parallelism achieved through superposition, is the equivalent of performing the same operation on a classical super computer with ~10150 separate processors (which is of course impossible)!!

Early investigators in this field were naturally excited by the potential of such immense computing power, and soon after realizing its potential, the hunt was on to find something interesting for a quantum computer to do. Peter Shor, a research and computer scientist at AT&T's Bell Laboratories in New Jersey, provided such an application by devising the first quantum computer algorithm. Shor's algorithm harnesses the power of quantum superposition to rapidly factor very large numbers (on the order ~10200 digits and greater) in a matter of seconds. The premier application of a quantum computer capable of implementing this algorithm lies in the field of encryption, where one common (and best) encryption code, known as RSA, relies heavily opon the difficulty of factoring very large composite numbers into their primes. A computer that can do this easily is naturally of great interest to numerous government agencies and anyone interested in electronic and financial privacy that use RSA (Rivest Shamir, and Adleman, a security algorithm that was previously considered to be uncrackable).

Encryption, however, is only one application of a quantum computer. Shor has also put together a toolbox of mathematical operations that can only be performed on a quantum computer, many of which he used in his factorization algorithm. Furthermore, Feynman asserted that “a quantum computer could function as a kind of simulator for quantum physics, potentially opening the doors to many discoveries in the field” (Dodge 67). Currently the power and capability of a quantum computer is primarily theoretical speculation; the advent of the first fully functional quantum computer will undoubtedly bring many new and exciting applications.

The idea of a computational device based on quantum mechanics was first explored in the 1970's and early 1980's by physicists and computer scientists such as Charles H. Bennett of the IBM Thomas J. Watson Research Center, Paul A. Benioff of Argonne National Laboratory in Illinois, David Deutsch of the University of Oxford, and the late Richard P. Feynman of the California Institute of Technology (Caltech). The idea emerged when scientists were pondering the fundamental limits of computation. They understood that if technology continued to abide by Moore's Law, then the continually shrinking size of circuitry packed onto silicon chips would “eventually reach a point where individual elements would be no larger than a few atoms” (Holtzman 90). It was here that a problem arose because at the atomic scale the physical laws that govern the behavior and properties of the circuit are inherently quantum mechanical in nature, not classical. This then raised the question of whether a new kind of computer could be devised based on the principles of quantum physics.

[harvestersel]

this is really cool information , ive send the link to my friends.

[digitalseo]

is this possible?...well the super computer will come soon...mathematicians theories and algorithms was recognized and implemented after so many decades...this is really amazing the fact that they are going to apply the principle of quantum physics...