Added Introduction to quantum information by Stephen M. Barnett (#9912)

* Added The physics of Quantum Computing

* Added Introduction to Quantum Information by Stephen M.Barnett

books/free-programming-books-subjects.md

@@ -775,6 +775,7 @@ Kerridge (PDF) (email address *requested*, not required)
 ### Quantum Computing
 
 * [Introduction to Classical and Quantum Computing](http://www.thomaswong.net/introduction-to-classical-and-quantum-computing-1e3p.pdf) - Thomas G. Wong (PDF)
+* [Introduction to Quantum Information](https://www.gla.ac.uk/media/Media_344957_smxx.pdf) - Stephen M. Barnett (PDF)
 * [Learn Quantum Computation using Qiskit](https://qiskit.org/textbook/preface.html) - Frank Harkins, et al. (HTML)
 * [Quantum Algorithms](https://arxiv.org/pdf/0808.0369v1) - Michele Mosca (PDF)
 * [Quantum Computing for the Quantum Curious](https://link.springer.com/book/10.1007/978-3-030-61601-4) - Ciaran Hughes, Joshua Isaacson, Anastasia Perry, Ranbel F. Sun, Jessica Turner (HTML, PDF, EPUB)