Programming Quantum Computers: Essential Algorithms and Code Samples

Programming Quantum Computers......Page 2
Revision History for the Early Release......Page 3
Required background......Page 4
What is a QPU?......Page 5
A Hands-on Approach......Page 6
  RUNNING CODE......Page 7
   Figure 1-2. The QCEngine UI......Page 8
  DEBUGGING CODE......Page 9
Native QPU Instructions......Page 10
 Simulator Limitations......Page 18
QPU vs. GPU: Some Common Characteristics......Page 19
How this book is structured......Page 20
 Figure 2-1. Possible values of a conventional bit - a graphical representation......Page 22
 Size of the circles:......Page 24
  WARNING......Page 25
A Quick Look at a Physical Qubit......Page 26
 Figure 2-7. A simple implementation of one photonic qubit......Page 27
HANDS-ON......Page 28
 QPU Instruction: NOT......Page 29
 QPU Instruction: HAD......Page 30
 QPU Instruction: READ and WRITE......Page 31
WHAT HAPPENED TO THE PHASE?......Page 32
  Figure 2-11. Generating a perfectly random bit with a QPU......Page 33
ABOUT THESE CODE SAMPLES......Page 34
EIGHT SEPARATE QUBITS......Page 35
  Figure 2-13. Operation of a PHASE gate......Page 36
  Figure 2-15. ROTX and ROTY actions on 0 and 1 input states.......Page 37
Combining QPU operations......Page 38
 QPU Combo Instruction: ROOT-of-NOT......Page 39
   NOTE......Page 40
Hands-on: Quantum Spy Hunter......Page 41
 Example 2-4. Quantum Random Spy Hunter......Page 42
Conclusion......Page 44
Circle notation for multi-qubit registers......Page 46
 Figure 3-1. Circle notation for various numbers of multiple qubits......Page 47
  TIP......Page 48
Drawing a Multi-Qubit Register......Page 49
Single-qubit Operations in Multi-Qubit Registers......Page 50
 Figure 3-6. Single-qubit phase in a multi-qubit register.......Page 51
Visualizing Larger Numbers of Qubits......Page 52
 Figure 3-8. Circle notation for larger qubit counts......Page 53
QPU Instruction: CNOT......Page 54
 Figure 3-10. CNOT in operation......Page 55
 Figure 3-13. Bell Pair step 2......Page 56
 TIP......Page 57
 Example 3-2. Make a Bell Pair......Page 58
QPU Instruction: CPHASE and CZ......Page 59
 Figure 3-16. Applying CPHASE in circle notation......Page 60
  Figure 3-18. Circuit for demonstrating phase kickback trick......Page 61
  Example 3-3. Phase Kickback......Page 62
Constructing Any Conditional Operation......Page 63
 Example 3-4. Custom conditional-phase......Page 64
QPU Instruction: CCNOT (Toffoli)......Page 65
QPU Instruction: SWAP and CSWAP......Page 67
 The swap test......Page 68
  Example 3-5. The swap test......Page 69
   Figure 3-27. How output of swap test varies as input states are made increasingly different......Page 70
   Figure 3-28. Number of swap tests that would need to return an outcome of 1 for us to be 99% confident inputs are identical......Page 71
 Example 3-6. Remote-controlled Randomness......Page 72
  Figure 3-29. The remote-random sample, step by step......Page 73
  Figure 3-31. The state of one qubit in the remote control after the other is READ to be 1.......Page 74
Conclusions......Page 75
 Figure 4-1. This chip is very small, so the qubit does not have far to go.1......Page 76
 Example 4-1. Teleport and verify......Page 77
  Figure 4-4. Teleportation circut in IBM QX6......Page 79
Program Step-by-step Walkthrough......Page 80
 STEP 2: PREPARE THE PAYLOAD......Page 81
  Figure 4-9. Step 3.1: Link the payload to the network......Page 82
 STEP 3.3: READ BOTH SEND QUBITS......Page 83
  Figure 4-12. Step 4: Receive and transform......Page 84
 STEP 5: VERIFY THE RESULT......Page 85
Interpreting the results......Page 86
Fun with famous teleporter accidents......Page 87
  Figure 4-17. Quantum Computing in the cloud......Page 88
  Example 4-2. Quantum Computing in the cloud......Page 89
  Example 4-3. Teleporting entanglement......Page 90
How is teleportation actually used?......Page 91
About the Authors......Page 93