Some light reading for a quantum physics post-doc. Inaccessible for most.
284 pages, ★★★
The topic is fascinating. Entangled photons (light ‘particles’) are known to exhibit what Einstein famously called “spooky action-at-a-distance”. Entangled photons exist in every possible state (and even in every possible position) until one of them is observed. The observation of one of the photons, no matter how far away it has travelled, instantly (literally instantly—at infinite speed—not just at the speed of light) influences the other photon by deciding its ‘state’. This has puzzled physicists for decades and has started to fascinate the public in recent years.
However, this book is inaccessible for me. I haven’t studied physics to this high a level. Its diagrams are incomprehensible for me because I’m not familiar with the symbols—and the book, foolishly, doesn’t define them. There are no analogies to help me understand these weird phenomena, and the characters (e.g. Einstein) don’t come to life to the extent that they do in Michio Kaku’s books. Entanglement makes light holidaying read for an established quantum physicist but is inaccessible and irrelevant to most other people. Fails to engage the public. ★★★
Excellent modern physics primer that’s mostly a biography of Einstein 203 pages, ★★★★
Author Michio Kaku is a very talented science writer. He is one of the few science writers who achieves the near-impossible goal of communicating advanced science accurately, in a way that’s easy to understand, and with added humour throughout. Most writers can’t do that!
In Einstein’s Cosmos, Kaku explores how Einstein’s life story shaped almost all of modern physics. The question of uniting two seemingly incompatible theories is a recurring theme in this book (and in physics itself). The first instance is on page 11, where we learn how Einstein was faced with the problem of reconciling Newton’s forces and Maxwell’s fields. “One of them had to fall”, Kaku writes. Einstein would topple Newtonian forces and replace them with something beautifully simple.
Kaku’s analogies are very easy to understand. To illustrate length contractions and time dilations using cars, he slows the speed of light down to 20mph and describes what each observer would see.
We’re now faced with an incompatibility between general relativity and quantum field theory. Both hold true at different scales, but they don’t seem to overlap properly as part of a grand “unifying theory”. Just as Einstein unified Newton’s and Maxwell’s equations, physicists are now faced with the task of unifying general relativity and quantum field theory—and the book almost exactly as it started.
Experiment 8: Mr. Einstein is on a railroad car moving to the left with velocity v, and on his car are two light bulbs that, from his perspective, come on simultaneously. To confirm this, he could also rig some sort of detector that would go off only if both beams of light arrive at his position simultaneously.
Question: What will Mrs. Einstein see?
Answer: She will agree that both beams of light reach Mr. Einstein at the same time. However, since from her point of view the light on the right has greater distance to travel, she will see the light on the right come on first!
Conclusion: From the above experiments we see that events which may be simultaneous for one observer can happen in a different sequence for another observer. This leads us to the startling conclusion that there is no such thing as a universal “now” for which everyone will agree on what happens “now”. That is, I can see two events as happening “now” while another observer will see one event happening “now” with the other event yet to occur!
I enjoy these bewildering thought experiments in special relativity. They stretch the mind for its own sake, like riddles, quizzes or a work of art. The more I think about the implications of Mr and Mrs Einstein on moving trains, the more I realise the triviality of our human senses. Our senses and feelings, as beguiling as they are, hardly represent the real world at all.
Recently, the number of books I’ve been reading has inflated my ego. This January, I read 21 books—that’s more than I read between the ages of 0 and 23. I’m also way ahead in this year’s Mad Reviewer Reading Challenge.
Thought experiments brought my ego back to normal again. Not special relativity, this time, but something much more useful…
Guided meditation. Thought experiments that sharpen your worldview.
190 pages, ★★★★★
Two thought experiments from this mid-level Buddhist book stood out for me.
First, everyone on earth is either your friend, neutral, or an enemy. Given that Buddhists believe in infinite reincarnation, everyone on earth has, at different points in the past, been your friend, neutral, and enemy. The author gives a political example:
“China was a close friend of the U.S. during the Second World War, then became an enemy during the Korean War, and now is supposedly a political friend again” — page 69
People also make up, make friends, and fall out within lifetimes. Given that all enemies can become friends, and that all friends can all become enemies, in this lifetime or the next, we can choose to mould the kinds of relationships we want in life.
The book phrases this much better (and longer) than I did, but the concluding ‘meditation’ is this:
“Just as I want happiness and don’t want suffering, so this friend wants happiness and doesn’t want suffering. And equally, this neutral person wants happiness and doesn’t want suffering. And equally, this enemy wants happiness and doesn’t want suffering.” — page 81
Irrefutable logic here cultivates your compassion for enemies, friends and strangers alike. So why not all get along?
Next, the ‘moon-ripples’ analogy, as I’ll call it, reminds us that our perception is just a mirage, a vague approximation of reality. The world behaves like the reflection of the moon in a rippled ocean:
“In the blink of an eye, everything is changing. Or, even more subtly, in each three-hundred-and-sixtieth of a blinking of an eye or of a snapping of the fingers, everything is disintegrating. For a Buddha, the realisation of this is still more subtle, but at our level, this measurement affords a glimpse of subtle change. It is said that all impermanent phenomena possess a nature of such subtle disintegration” — page 171
We fixate on false ideals and try to solidify the future. This is an impossible goal, since the world is unpredictably complex; elusive and in constant flux. The future is never certain, nor should it be. When you encounter something you will never understand or see clearly, just think about the ‘moon-ripples’ analogy.
This interactive book is written for people already familiar with Buddhism. Author Jeffrey Hopkins uses his experience from the Tibetan Buddhist Learning Center in the United States to formulate these exercises. There are dozens of meditations, and pages of prose provide the supporting logic behind each one. Everyone will find something they need in this book—I recommend Cultivating Compassion for all Buddhists. ★★★★★
An inconclusive book on an inconclusive subject.
416 pages, ★★★★
Physics is dead. Or maybe it’s just finished. According to the Trouble with Physics, no significant progress has been made towards a ‘grand unifying theory’ since the 1980s. Unfortunately, that was when the author started his physics career.
Theories are developed that fit the available evidence at the time. According to Popper, “a theory is only good until it’s falsified”, and according to Einstein, “a theory should be as simple as it can possibly be, but no simpler”. Theories thus tend to be simple (at least in retrospect) and short-lived.
The trouble with physics comes with the most recent theory, String Theory. It’s neither simple nor short-lived. In fact, it’s so complicated that most physicists don’t fully understand it (or that’s what they claim), and because it can never be proven or disproven, it is effectively permanent. Author Lee Smolin talks about the quasi-religious following surrounding String Theory and its excessive derision of critics. To me, the String Theory lobby sounds about as entrenched as that of climate change, or of intelligent design. If that’s the case, then physics is definitely finished.
As a newcomer to physics, I learned a lot of theory from this book. I learned about General Relativity, Quantum Theory, Loop Quantum Gravity, Technicolor, Twistor Theory and MSSM theory; and the discoveries made by Aristotle, Kepler, Galileo, de Sitter, Einstein, Kelvin, Eddington, Popper and many, many more. Despite the level of detail in this book, math is used only sparingly—which is why I chose this book over others.
The Trouble With Physics is suitable for non-physicists who want to reassure themselves that they made the right career choice. In just 416 pages, The Trouble with Physics provides enough background information to understand passing conversations with physicists, and to understand almost all Big Bang Theory jokes. This book is the most readable in its category. ★★★★