(It's not, I think, one of the Greeks or minor Greeks, but I posted here thinking this group might be more mathematically minded.) Anyway, is there a term for the phenomena by which a call going into the money (or a stock or future rising) will do so slower than a put going ITM (or stock or futures falling), when the move is large and sharp -- meaning, say, over 3 percent in less than one day? I'm looking for like speed or velocity or something. (Maybe it has something to do with the put-call ratio, but I don't think so, as that is volume, but hey, who knows?)
Not true, similiary as to how phase velocity can exceed the speed light with a concomitant drop in group velocity and vice versa. I need to look at the rough Heston model to see if it v directly models this or can capture assymetry there
No thing can exceed the speed of light, not even light itself. And don't speak about tachyons. Are you calling Einstein a dumbass?
Not really what Heston was about. Heston is about a "better" non-constant estimate for volatility and price path - not parity. Screw up parity and the blind would trade it. Heston only really addresses Europen index options. The parity pair might have better absolute estimate of volatility. Blow parity and there are huge low risk or risk free if it's SPX - opportunities. Plus you would have the disparity showcased to hundreds of MM and thousands of customers.
gamma differential between calls and puts? I don't think so. Options react to underlying's price movements differently from time to time but not in a fixed systematic fashion, the least according to option types. That's my observation anyway. There might be studies out there that might prove otherwise, that I dunno.