Quantum Computing Presented by: Poomipat Phusayangkul Monsit Pornnumpa
Richard P. Feynman Charles H. Bennett David Deutsch History of QuanTum Computer • The idea of a computational by physicists and computer scientists like: Charles H. Bennett Paul A. Benioff David Deutsch Richard P. Feynman 1982:Feynman explained how such quantum computer would be able to act as a simulator for quantum physics. 1985:Deutsch realized that Feynman's assertion could eventually lead to a general purpose quantum computer and published a crucial theoretical paper. 1994: Unfortunately, all that could be found were a few rather contrived mathematical problems.
Device for computation that makes direct use of • superpositionandentanglement, to perform • operations on data. • In a quantum computer, the amount of data is • measured byqubits. • Quantum properties of particles can be used to • represent and structure data. WHAT is QUANTUM COMPUTER?
Coherent Superposition • A qubit can exist in states corresponding to a blend or superposition of these classical • states. • A qubit can exist simultaneously as both 0 and 1. Experiment of Coherent Superposition:
Entanglement • A quantum mechanical phenomenon in which of two or more objects reference to each other. • It is possible to prepare two particles in a single quantum state such when one is spin-up, another one will always spin-down and vice versa. As a result, measurements performed on one system seem to be instantaneously influencing other systems entangled with it. Closely concerned with the emerging technologies of quantum computing, cryptography, and teleportation.
Classical VS Quantum • Consider first a classical computer that operates on a 3 bit • register. • Qubits can be in a superposition of all the classically allowed states. For an n qubit quantum register, recording the state of the register requires 2n complex numbers. Number of classical states encoded in a quantum register grows exponentially with the number of qubits.
Quantum computer could solve Integer factorization problem easily. • Most of the popular public key ciphers could be much more quickly broken, including forms of RSA, ElGamaland Diffie-Hellman. The time for a quantum computer to solve a problem will, reducing from years to seconds. Quantum chip ! QUANTUM POWER ! • Consider a problem that has these four properties: • The only way to solve it is to guess answers repeatedly and check them. • There are n possible answers to check. • Every possible answer takes the same amount of time to check. • There are no clues about which answers might be better: generating possibilities randomly is just as good as checking them in some special order.
an ion-trap the core of a quantum computer Obstacle in building Quantum Computer • The field of quantum information processing has made numerous promising advancements since its conception, However, a few potentially large obstacles still remain that prevent us from just building one. Below are the list of requirements for a practical quantum computer: • scalable physically to increase the number of • qubits • qubits can be initialized to arbitrary values • quantum gates faster than decoherence time • Turing-complete gate set • qubits can be read easily What errors need correction? To date, the designs of quantum computer involved ion traps, cavity quantum electrodynamics (QED), and NMR.
Reference http://en.wikipedia.org/wiki/Quantum_computer http://www.cs.caltech.edu/~westside/quantum-intro.html In Thai http://www.kitty.in.th/index.php?room=article&id=80 THE END