Quantum computing is gaining global attention—not just among physicists, but also among computer scientists, engineers, and even high school students curious about the future of technology. As more people enter the field, one common question arises:
“Do I really need to know quantum mechanics to study quantum computing?”
This is not just a theoretical debate. It matters for educators designing curricula, for students choosing courses, and for professionals wondering whether they can contribute without a physics background. Let me share my own journey and reflections on this important question.
A Question from a Symposium
About six months ago, I gave a short talk on my quantum computing work at a small symposium. During the Q&A, one professor asked me exactly this question. At the time, I answered:
“Quantum computing leans more toward information science, so quantum mechanics isn’t absolutely necessary—but sometimes it becomes important.”
That wasn’t entirely wrong. But after thinking it over, I’ve come to a clearer conclusion.
Quantum Mechanics Is Essential
It’s actually more accurate to say: yes, quantum mechanics is essential.
That doesn’t mean computer science students, for example, must take a full course in quantum mechanics before diving in. Most introductory textbooks on quantum computing already begin with the very basics of quantum mechanics—like the behavior of qubits—because without that foundation, you can’t even start the discussion. In that sense, it’s possible to step into quantum computing directly through these resources.
When a Deeper Foundation Becomes Necessary
As your study progresses, though—especially when working on applications in physics, chemistry (energy-related problems in particular), or optimization—you’ll need at least an undergraduate-level understanding of quantum mechanics.
In my case, I’ve spent most of my career in information technology, but in recent years I’ve been exploring quantum computing as an “amateur researcher.” Feeling the need to revisit the fundamentals, I found a book that turned out to be ideal:
Leonard Susskind & Art Friedman, Quantum Mechanics: The Theoretical Minimum, Penguin Books, 2014 (364 pages).
(A free PDF version is available online.)
Learning from Prof. Susskind
Prof. Leonard Susskind is a world-renowned physicist, and his coauthor Art Friedman is a former student. The book grew out of a ten-lecture series given at Stanford University for Silicon Valley engineers. That origin gives the text both rigor and clarity.
It’s not a breezy read, though. Even though the theory is pared down to the “minimum,” you still need to carefully work through the calculations. It took me about two months to complete a first pass, and I still revisit key sections. But the reward was immense: I rediscovered insights rarely emphasized in standard quantum computing texts, such as:
Observables (physical quantities) are represented by linear operators.
The time derivative of an expectation value is related to another physical quantity.
These concepts may sound abstract, but they capture the very essence of quantum mechanics.
My Study Approach
🟢 To keep myself motivated, I decorated the book’s cover with bright designs and added sticky notes for each chapter, giving me a quick visual map of its structure. For me, study works best when it feels both serious and fun.
Final Thoughts
So, is quantum mechanics necessary for learning quantum computing?
Yes—without question.
You don’t need to master quantum mechanics before you start, since most textbooks will guide you through the basics. But if you aim to go further—to tackle real applications, explore research, or simply gain a deeper understanding—you will eventually need the solid grounding that only quantum mechanics can provide.
Fortunately, resources like Susskind’s The Theoretical Minimum make that journey both possible and rewarding. And with the global surge in interest, now is the perfect time to embrace both the physics and the computing sides of this exciting field.
