## Errata

- In Figure 3.28 at the top of Page 86, the angle on the right side of the diagram is 9pi/4, not 5pi/4. (Thanks to Arend Smit for bringing this to my attention.)
- In the second bullet on Page 177, "... applying H to |1> gives us (1/sqrt(2))(|0>
**–** |1>), also known as |–>. (Thanks again to Arend Smit.) - The equations on Pages 210 to 212 are all correct, but they're not consistent with one another.
- Several Qiskit features in the book's code have been made obsolete by the release of Qiskit 1.0.1 in February 2024. I will be posting updates for the code at https://github.com/PacktPublishing/Quantum-Computing-Algorithms. One example: Before releasing v1.0 of Qiskit, IBM had two methods (named
`cnot`

and `cx`

) that were identical to one another. In my book, I used `cnot`

. When IBM released v1.0 this month, they eliminated cnot in favor of `cx`

. There are at least two ways to fix the code in my book:

- Change every occurrence of `cnot`

to `cx`

.

- Run the following line at the start of each program: `QuantumCircuit.cnot = QuantumCircuit.cx`

(Thanks to Fujio Yamamoto.)
- In the first line of Page 263, replace the words
*In entry 1* with the words *In entry 0*. (Thanks to Fujio Yamamoto.)
- At the bottom of Page 248, replace

\( {\frac{1}{\sqrt2}}\ \vee0\rangle\ +\ {\frac{1}{\sqrt2}}\ \vee1\rangle\) to \({\frac{1}{\sqrt2}}\ \vee0\rangle\ +\ i\ {\frac{1}{\sqrt2}}\ \vee1\rangle \)

with

\( {\frac{1}{\sqrt2}}\ |0\rangle\ +\ {\frac{1}{\sqrt2}}\ |1\rangle\) to \({\frac{1}{\sqrt2}}\ |0\rangle\ +\ i\ {\frac{1}{\sqrt2}}\ |1\rangle \).

(Thanks to Fujio Yamamoto.)
- In the discussion on Pages 252 to 254, I omitted the
*i* in exponents of *e*. Here are some corrections surrounding that omission:

Figure 9.13

Figure 9.14

Figure 9.15

The equation at the bottom of Page 253: \( e^{i\pi/2} \cdot e^{i\pi} = e^{i(\pi/2 + \pi)} = e^{i \cdot (3\pi/2)} \)

Figure 9.16

(Thanks to Fujio Yamamoto.)
- In the book, Figure 9.27 is for a run that uses coprime 11. Here's a figure with the initialization numbers for coprime 7:

Figure 9.13

(Thanks to Fujio Yamamoto.)