Are we quantum computers, or merely clever robots?

I would like to tell you about a new topic in “applied” quantum mechanics that has been my obsession for the past four years, summarized succinctly in my intentionally provocative title “Are we quantum computers, or merely clever robots?” My story starts not with quantum mechanics, but with lithium–the 3rd simplest atom but also a psychiatric drug remarkable in its efficacy against serious mood disorders. Lithium–the Liion alone–is the drug of choice in “tempering mania and bipolar disorder”, employed by millions of people towards this end in the United States since 1974. I, myself, have taken lithium on and off for many years, and have always been fascinated by how a single element can be such an effective drug. Four years ago I set out with determination to uncover the biochemical mechanism behind lithium’s potency. While there are many medications for fighting depression, bipolar disorder and other debilitating psychiatric disorders, all of these drugs are complex molecules with 10–20 atoms. So lithium’s simplicity was its attraction to me as a physicist. The joke that a physicist, when asked to understand a cow, would begin with the “spherical cow approximation” is, for lithium, no joke at all: Since the Liion has 2 electrons in the 1s atomic orbital it is “exactly” a sphere. For lithium the “spherical drug approximation” is NOT an approximation. I reasoned that if we cannot understand lithium’s biochemical mode of operation on cognition, there would be little hope to determine the mechanism behind the efficacy of any of the complex molecular psychiatric pharmaceuticals. Lithium has two stable isotopes, lithium-7 and lithium-6, as I soon learned. The natural abundance of lithium is 92% Li-7 and 8% Li-6. So when one takes lithium as a pharmaceutical one is predominantly taking lithium-7.