out from under the two stools as if the invitation were extended to him.
‘Yes. Where?’
‘I know a place.’ Harry rose, unhooked his coat from the back of the bar chair. ‘Then I can tell you about my cat.’
‘Cat?’
‘Her name is Schrödinger.’
‘Good name for a cat.’
‘I think you’ll like her.’
SCHRÖDINGER’S CAT
9
‘Schrödinger’s equation–’ Harry began.
‘I thought that was your cat’s name.’
‘It is. My cat’s named after the physicist Schrödinger.’
‘If I were your cat, I’d object.’ Jury felt Mungo twisting around on his feet as if he’d object, too.
‘The Schrödinger equation is famous; it might be the greatest contribution to quantum mechanics besides Niels Bohr’s.’ Jury sipped a very good single malt. They had forgone the wine list in favor of whiskey. The Docklands restaurant was crowded with up-and-comers, you could tell, along with the chattering classes.
‘Am I going to like this?’
‘You’ll love it. There’s a thought experiment in quantum physics–no, a hypothesis–and it’s very interesting: you put a cat in a box along with a vial containing cyanide, together with a radioactive nucleus and a mechanism to trace the decay. Now, the nucleus has to decay; it’s when the nucleus will decay that we don’t know. But when the nucleus decays, it nudges the mechanism that releases the poison. The poison leaks out and kills the cat.’
‘I’m notifying PETA.’
Harry winced. ‘You don’t do it, for God’s sake; you don’t kill the cat. The point is this: you have only probability to go on that the nucleus will decay by a certain time. Nuclear decay is unpredictable. As I said, it will decay, you just don’t know when; and, of course, you might open the box before the nucleus decays. But you don’t know when or if the cat will die. Now, we know that the nucleus hasn’t decayed, and the cat is alive only when we close the lid of the box. You could say that’s our final measurement until we open it again. All we have to go on is wave function–the wave function of the nucleus–’
‘What in hell’s that?’ Jury was feeling both relatively drunk and relatively stupid.
‘It’s hard to describe exactly. Say this: in classical physics–’
‘Einstein,’ put in Jury, feeling better.
Harry smiled. ‘Good. In classical physics, an electron can be said to have a certain position. But in quantum mechanics, no. The wave function defines an area, say, of probability. An analogy might be that if a highly contagious disease turns up in a segment of the population, the disease control center gets right on it and tries to work out the probability of its recurrence in certain areas. The wave function isn’t an entity, it’s nothing in itself, it describes probability.’ Harry leaned closer as if he were divulging a sexy secret and went on: ‘So what we’ve got, then, is the probability of an electron’s being in a certain place at a certain moment. Only when we’re measuring it can we know not only where it is but if it is. So the cat–’ Jury waved his hands in front of his face as if clearing a space to breathe in. ‘Are you going to tell me the cat’s both alive and dead at the same time?’
Harry smiled. ‘That’s right.’
Jury made a blubbery sound with his lips. ‘That’s ridiculous.’
‘No, it isn’t. You just don’t understand. The decayed/undecayed nucleus is entangled with the live/dead cat–’
Mungo stuck his head out and looked, Jury could have sworn, balefully up at him. The dog pulled his head back under the tablecloth.
Jury laughed.
‘What?’
‘Mungo seems to be entangled with your zombie cat! The undead.’
‘He can’t stand the cat; he never could.’
‘I sympathize.’ Jury lifted the cloth, said this, let it fall.
‘To continue: Niels Bohr made it clear that, of course, the cat wasn’t literally dead and alive at the same time, but in the absence of measurement, there’s no
‘Yes. Where?’
‘I know a place.’ Harry rose, unhooked his coat from the back of the bar chair. ‘Then I can tell you about my cat.’
‘Cat?’
‘Her name is Schrödinger.’
‘Good name for a cat.’
‘I think you’ll like her.’
SCHRÖDINGER’S CAT
9
‘Schrödinger’s equation–’ Harry began.
‘I thought that was your cat’s name.’
‘It is. My cat’s named after the physicist Schrödinger.’
‘If I were your cat, I’d object.’ Jury felt Mungo twisting around on his feet as if he’d object, too.
‘The Schrödinger equation is famous; it might be the greatest contribution to quantum mechanics besides Niels Bohr’s.’ Jury sipped a very good single malt. They had forgone the wine list in favor of whiskey. The Docklands restaurant was crowded with up-and-comers, you could tell, along with the chattering classes.
‘Am I going to like this?’
‘You’ll love it. There’s a thought experiment in quantum physics–no, a hypothesis–and it’s very interesting: you put a cat in a box along with a vial containing cyanide, together with a radioactive nucleus and a mechanism to trace the decay. Now, the nucleus has to decay; it’s when the nucleus will decay that we don’t know. But when the nucleus decays, it nudges the mechanism that releases the poison. The poison leaks out and kills the cat.’
‘I’m notifying PETA.’
Harry winced. ‘You don’t do it, for God’s sake; you don’t kill the cat. The point is this: you have only probability to go on that the nucleus will decay by a certain time. Nuclear decay is unpredictable. As I said, it will decay, you just don’t know when; and, of course, you might open the box before the nucleus decays. But you don’t know when or if the cat will die. Now, we know that the nucleus hasn’t decayed, and the cat is alive only when we close the lid of the box. You could say that’s our final measurement until we open it again. All we have to go on is wave function–the wave function of the nucleus–’
‘What in hell’s that?’ Jury was feeling both relatively drunk and relatively stupid.
‘It’s hard to describe exactly. Say this: in classical physics–’
‘Einstein,’ put in Jury, feeling better.
Harry smiled. ‘Good. In classical physics, an electron can be said to have a certain position. But in quantum mechanics, no. The wave function defines an area, say, of probability. An analogy might be that if a highly contagious disease turns up in a segment of the population, the disease control center gets right on it and tries to work out the probability of its recurrence in certain areas. The wave function isn’t an entity, it’s nothing in itself, it describes probability.’ Harry leaned closer as if he were divulging a sexy secret and went on: ‘So what we’ve got, then, is the probability of an electron’s being in a certain place at a certain moment. Only when we’re measuring it can we know not only where it is but if it is. So the cat–’ Jury waved his hands in front of his face as if clearing a space to breathe in. ‘Are you going to tell me the cat’s both alive and dead at the same time?’
Harry smiled. ‘That’s right.’
Jury made a blubbery sound with his lips. ‘That’s ridiculous.’
‘No, it isn’t. You just don’t understand. The decayed/undecayed nucleus is entangled with the live/dead cat–’
Mungo stuck his head out and looked, Jury could have sworn, balefully up at him. The dog pulled his head back under the tablecloth.
Jury laughed.
‘What?’
‘Mungo seems to be entangled with your zombie cat! The undead.’
‘He can’t stand the cat; he never could.’
‘I sympathize.’ Jury lifted the cloth, said this, let it fall.
‘To continue: Niels Bohr made it clear that, of course, the cat wasn’t literally dead and alive at the same time, but in the absence of measurement, there’s no
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