26 operation, 451, 476, 477, 481, 488, 491, 492, 499, QIT, see Quantum information theory 508, 556, 667 QKD, see Quantum key distribution parallelism, 378, 380, 383 Quanta (energy), 544 repetition code, 496-503 Quantum state, see State bit, see Qubit teleportation, see Teleportation channel, 431, 450-4, 475, 476, 497, 559, 561, wire, 381 Quarter-wave plate, see Wave plate capacity, 482, 487-93 Qubit, xix, 304-10, 334, 435 communication, 476 amplitude, 306 bit-flip, 475, 479-80, 491-3, 496, 497 ancilla, 370, 379, 401 bit-phase-flip, 475, 480-1 control, 316 depolarizing, 475, 477-8, 488-91 entangled, 356 ideal or noiseless, 475, 476, 489 joint, 356 nonideal or noisy, 477, 481, 498 target, 316, 370 phase-flip, 475, 480, 496, 501 teleportation, see Teleportation useless, 478, 493 two (-), 309 channel capacity, 475 vector, 334 circuit, XX, 304, 314, 322-7 wire, 381 code, 484 Qudit, 372 codeword, 457 Quincunx, 34 coherence, 561 QuNit/qunit, 372, 435 coherent information, see Information Qutrit, 374 compression, 457-64 computation/computing, xix, 305, 310, 311, 356, Random-number generation, 191, 563 378, 380 computer, XX, 310, 398, 399, 536 bit error (-), see Bit error rate cryptography, see Cryptography code (-), see Code decoherence, XX, 561 compression (-), see Compression distributed (-) computing, 356 parameter, 28 energy/light (quanta), 23, 25, 65 Rational number, 408 entanglement, see Entanglement Rayleigh distribution, see Probability error, 457 Receiver, 208 bit-flip (-), 506, 507 Recipient, 37, 40, 41 phase-flip (-), 505, 507 Red Book, 592 error correction, xx, 496, 497, 562 Redundancy (code), see Code Calderbank-Shor-Steane (CSS), 496, 509, Reed-Solomon codes, see Code 511, 513 Register, 289, 290, 301, 382 Hadamard-Steane, 496, 514-20 Relative entropy, see Entropy Shor (-) code, xx, 496, 503-9 Relativity (theory), see Einstein Fourier transform, XV, xix, 378, 383-9, 403, Reliability function, see Function 644-7 Rényi, A., 45 gate, xx, 311, 314, 374 REPEAT gate, 294, 297, 312 gate teleportation, see Teleporta