Einstein and Schrödinger had just completed a mammoth effort of once again trying to unite quantum mechanics and general relativity, which Einstein had tried to do for most of his life. In reviewing his latest results, Einstein wrote to Schrödinger that his results looked like “a gift from the devil’s grandmother.”<2007 “We [[physicists, Albert Einstein and Erwin Schrödinger]] have squandered a lot of time on this, and the result looks like a gift from the devil’s grandmother.”—Einstein: His Life and Universe by Walter Isaacson, page 513>
Schrödinger wrote back to Einstein, “I have not laughed so much for a long time as over the ‘gift of the devils grandmother.’ For in the preceding sentences you described the way of the cross [[see future posting]] that I also traveled in order to end up with something even more impossible than your result.”
I take this phrase to mean that so intricately convoluted and complex, as intricate as needlework (assuming grandmothers do needlework) from a mad-women, had his work become so as to be somewhat discouraging. However, Einstein never gave up and was unsuccessful in his quest. He soldiered on (but to no avail) because he just couldn’t believe that real physical quantities had to be determined by probabilities as quantum mechanics would have it. To this day no one has figured out how to unite General Relativity with quantum mechanics.
This phrase was never picked up for use by others and so it remains a one-off by Albert Einstein.
Ken Greenwald — December 9, 2017