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Financial supports from Kinki Univ., MEXT and JSPS. Computing with Quanta for mathematics students. Mikio Nakahara Department of Physics & Research Centre for Quantum Computing Kinki University, Japan. Table of Contents. 1. Introduction: Computing with Physics
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Financial supports from Kinki Univ., MEXT and JSPS Computing with Quantafor mathematics students Mikio Nakahara Department of Physics & Research Centre for Quantum Computing Kinki University, Japan
Table of Contents • 1. Introduction: Computing with Physics • 2. Computing with Vectors and Matrices • 3. Brief Introduction to Quantum Theory • 4. Quantum Gates, Quantum Circuits and Quantum Computer • 5. Quantum Teleportation • 6. Simple Quantum Algorithm • 7. Shor’s Factorization Algorithm Colloquium @ William & Mary
I. Introduction: Computing with Physics Colloquium @ William & Mary
More complicated Example Colloquium @ William & Mary
Quantum Computing/Information Processing • Quantum computation & information processing make use of quantum systems to store and process information. • Exponentially fast computation, totally safe cryptosystem, teleporting a quantum state are possible by making use of states & operations which do not exist in the classical world. Colloquium @ William & Mary
Table of Contents • 1. Introduction: Computing with Physics • 2. Computing with Vectors and Matrices • 3. Brief Introduction to Quantum Theory • 4. Quantum Gates, Quantum Circuits and Quantum Computer • 5. Quantum Teleportation • 6. Simple Quantum Algorithm • 7. Shor’s Factorization Algorithm Colloquium @ William & Mary
2. Computing with Vectors and Matrices2.1 Qubit Colloquium @ William & Mary
Qubit |ψ〉 Colloquium @ William & Mary
Bloch Sphere: S3→ S2 π Colloquium @ William & Mary
2.2 Two-Qubit System Colloquium @ William & Mary
Tensor Product Rule Colloquium @ William & Mary
Entangled state (vector) Colloquium @ William & Mary
2.3 Multi-qubit systems Colloquium @ William & Mary
2.4 Algorithm = Unitary Matrix Colloquium @ William & Mary
Unitary Matrices acting on n qubits Colloquium @ William & Mary
Table of Contents • 1. Introduction: Computing with Physics • 2. Computing with Vectors and Matrices • 3. Brief Introduction to Quantum Theory • 4. Quantum Gates, Quantum Circuits and Quantum Computer • 5. Quantum Teleportation • 6. Simple Quantum Algorithm • 7. Shor’s Factorization Algorithm Colloquium @ William & Mary
3. Brief Introduction to Quantum Theory Colloquium @ William & Mary
Axioms of Quantum Physics Colloquium @ William & Mary
Example of a measurement Colloquium @ William & Mary
Axioms of Quantum Physics (cont’d) Colloquium @ William & Mary
Qubits & Matrices in Quantum Physics Colloquium @ William & Mary
Actual Qubits Trapped Ions Neutral Atoms Molecules (NMR) Superconductors Colloquium @ William & Mary
Table of Contents • 1. Introduction: Computing with Physics • 2. Computing with Vectors and Matrices • 3. Brief Introduction to Quantum Theory • 4. Quantum Gates, Quantum Circuits and Quantum Computer • 5. Quantum Teleportation • 6. Simple Quantum Algorithm • 7. Shor’s Factorization Algorithm Colloquium @ William & Mary
4. Quantum Gates, Quantum Circuit and Quantum Computer Colloquium @ William & Mary
4.2 Quantum Gates Colloquium @ William & Mary
Hadamard transform Colloquium @ William & Mary
4.3 Universal Quantum Gates Colloquium @ William & Mary
4.4 Quantum Parallelism Colloquium @ William & Mary
Table of Contents • 1. Introduction: Computing with Physics • 2. Computing with Vectors and Matrices • 3. Brief Introduction to Quantum Theory • 4. Quantum Gates, Quantum Circuits and Quantum Computer • 5. Quantum Teleportation • 6. Simple Quantum Algorithm • 7. Shor’s Factorization Algorithm Colloquium @ William & Mary
5. Quantum Teleportation Unknown Q State Bob Initial State Alice Colloquium @ William & Mary
Q Teleportation Circuit Colloquium @ William & Mary
As a result of encoding, qubits 1 and 2 are entangled. When Alice measures her qubits 1 and 2, she will obtain one of 00, 01, 10, 11. At the same time, Bob’s qubit is fixed to be one of the four states. Alice tells Bob what readout she has got. Upon receiving Alice’s readout, Bob will know how his qubit is different from the original state (error type). Then he applies correcting transformation to his qubit to reproduce the original state. Note that neither Alice nor Bob knows the initial state Example: 11 Colloquium @ William & Mary
Table of Contents • 1. Introduction: Computing with Physics • 2. Computing with Vectors and Matrices • 3. Brief Introduction to Quantum Theory • 4. Quantum Gates, Quantum Circuits and Quantum Computer • 5. Quantum Teleportation • 6. Simple Quantum Algorithm • 7. Shor’s Factorization Algorithm Colloquium @ William & Mary
5. Simple Quantum Algorithm- Deutsch’s Algorithm - Colloquium @ William & Mary
Table of Contents • 1. Introduction: Computing with Physics • 2. Computing with Vectors and Matrices • 3. Brief Introduction to Quantum Theory • 4. Quantum Gates, Quantum Circuits and Quantum Computer • 5. Quantum Teleportation • 6. Simple Quantum Algorithm • 7. Shor’s Factorization Algorithm Colloquium @ William & Mary
Difficulty of Prime Number Facotrization • Factorization of N=89020836818747907956831989272091600303613264603794247032637647625631554961638351 is difficult. • It is easy, in principle, to show the product of p=9281013205404131518475902447276973338969 and q =9591715349237194999547 050068718930514279 is N. • This fact is used in RSA (Rivest-Shamir-Adleman) cryptosystem. Colloquium @ William & Mary
Shor’s Factorization algorithm Colloquium @ William & Mary
Realization using NMR (15=3×5)L. M. K. Vandersypen et al (Nature 2001) Colloquium @ William & Mary
NMR molecule and pulse sequence ( (~300 pulses~ 300 gates) perfluorobutadienyl iron complex with the two 13C-labelled inner carbons Colloquium @ William & Mary
Foolproof realization is discouraging …? Vartiainen, Niskanen, Nakahara, Salomaa (2004) Foolproof implementation of factorization 21=3 X 7 with Shor’s algorithm requires at least 22 qubits and approx. 82,000 steps! Colloquium @ William & Mary
Summary • Quantum information is an emerging discipline in which information is stored and processed in a quantum-mechanical system. • Quantum information and computation are interesting field to study. (Job opportunities at industry/academia/military). • It is a new branch of science and technology covering physics, mathematics, information science, chemistry and more. • Thank you very much for your attention! Colloquium @ William & Mary
4. 量子暗号鍵配布 三省堂サイエンスカフェ 2009年6月
量子暗号鍵配布 1 三省堂サイエンスカフェ 2009年6月
量子暗号鍵配布 2 三省堂サイエンスカフェ 2009年6月