Physicists Can Predict the Jumps of Schrodinger's Cat (and Finally Save It) (phys.org) 175
An anonymous reader quotes a report from Phys.Org: Yale researchers have figured out how to catch and save Schrodinger's famous cat, the symbol of quantum superposition and unpredictability. In the process, they overturn years of cornerstone dogma in quantum physics. Schrodinger's cat is a well-known paradox used to illustrate the concept of superposition -- the ability for two opposite states to exist simultaneously -- and unpredictability in quantum physics. The idea is that a cat is placed in a sealed box with a radioactive source and a poison that will be triggered if an atom of the radioactive substance decays. The superposition theory of quantum physics suggests that until someone opens the box, the cat is both alive and dead, a superposition of states. Opening the box to observe the cat causes it to abruptly change its quantum state randomly, forcing it to be either dead or alive. The quantum jump is the discrete (non-continuous) and random change in the state when it is observed.
The experiment, performed in the lab of Yale professor Michel Devoret and proposed by lead author Zlatko Minev, peers into the actual workings of a quantum jump for the first time. The Yale team used a special approach to indirectly monitor a superconducting artificial atom, with three microwave generators irradiating the atom enclosed in a 3-D cavity made of aluminum. The doubly indirect monitoring method, developed by Minev for superconducting circuits, allows the researchers to observe the atom with unprecedented efficiency. Microwave radiation stirs the artificial atom as it is simultaneously being observed, resulting in quantum jumps. The tiny quantum signal of these jumps can be amplified without loss to room temperature. Here, their signal can be monitored in real time. This enabled the researchers to see a sudden absence of detection photons (photons emitted by an ancillary state of the atom excited by the microwaves); this tiny absence is the advance warning of a quantum jump. The study has been published in the journal Nature.
The experiment, performed in the lab of Yale professor Michel Devoret and proposed by lead author Zlatko Minev, peers into the actual workings of a quantum jump for the first time. The Yale team used a special approach to indirectly monitor a superconducting artificial atom, with three microwave generators irradiating the atom enclosed in a 3-D cavity made of aluminum. The doubly indirect monitoring method, developed by Minev for superconducting circuits, allows the researchers to observe the atom with unprecedented efficiency. Microwave radiation stirs the artificial atom as it is simultaneously being observed, resulting in quantum jumps. The tiny quantum signal of these jumps can be amplified without loss to room temperature. Here, their signal can be monitored in real time. This enabled the researchers to see a sudden absence of detection photons (photons emitted by an ancillary state of the atom excited by the microwaves); this tiny absence is the advance warning of a quantum jump. The study has been published in the journal Nature.
Well, if we have the (Score:5, Interesting)
Heisenberg compensators, I guess transporters are next?
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Hello Pixel [wikipedia.org]!
Quantum encryption is dead (Score:1, Interesting)
So, now secure quantum computing is dead, but the cat is alive.
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And the fact that this has been modded up goes to show how well people on these site really understand about physics.
Get your education from a genuine school or educational book perhaps and not from a SciFi TV show with notoriously bad science.
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Heisenberg's Uncertainty Principle and SchrÃdinger's Cat are fundamentally different phenomenon in physics.
And the fact that this has been modded up goes to show how well people on these site really understand about physics.
Get your education from a genuine school or educational book perhaps and not from a SciFi TV show with notoriously bad science.
Importantly SchrÃdinger's Cat was SchrÃdinger's attempt to debunk early ideas of how to interpret quantum mechanics. While people still talk about the Copenhagen interpretation, it's mostly out of habit at this point, nearly 100 years later. The notion that "collapsing he wave state" is a physical process, rather than a mathematical/conceptual tool, isn't so common any more.
Lots of the early explanations/interpretation of QM have been abandoned under the weight of experiment. The Quantum world s
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However my point is that this is very distinct from the Uncertainty Principle, which describes a phenomenon that fundamentally limits our ability for precise measurements. And it should therefore not be conflated.
I suppose some of the Trek fans pointed this out to the Trek writers some ti
What Absolute Horse Shit. (Score:2, Informative)
Schrodinger's cat is a well-known paradox used to illustrate the concept of superposition -- the ability for two opposite states to exist simultaneously -- and unpredictability in quantum physics.
It's not a paradox, it's a thought experiment meant to show the absurdity of the many-worlds interpretation.
Re:What Absolute Horse Shit. (Score:5, Informative)
It's not a paradox, it's a thought experiment meant to show the absurdity of the many-worlds interpretation.
Nope.
The cat thought-experiment was described by Schrodinger in 1935.
The many-worlds hypothesis was first proposed by Hugh Everett in 1957.
Re:What Absolute Horse Shit. (Score:5, Insightful)
It was intended to show the absurdity of the Copenhagen interpretation. Many worlds is different from Copenhagen, but it's a direct descendant of it.
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More specifically, it tried to show that if you accepted the Copenhagen interpretation it was easy to extrapolate a situation where even life and death became undefined.
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Life and death is fuzzily defined. It's a serious problem in medical ethics.
Is an otherwise healthy person with zero brain activity alive or dead?
What about someone conscious but heart has stopped?
An unconscious person with a stopped heart?
A person who could probably be resuscitated but currently has no signs of life.
A 25-week fetus/baby?
A 25-week fetus/baby outside the mother?
Same two questions, but now they are both unwanted by the mother.
Same two questions, but change the number over and over and over.
Li
Re:What Absolute Horse Shit. (Score:5, Funny)
The cat thought-experiment was described by Schrodinger in 1935.
Whaddya mean thought-experiment ?!?!?
And here along all these years I've been trying to replicate the real thing.
And the woman at the animal shelter asks me always why the last ones died, when I go there to pick up another crop.
I always tell here to google on Schrödinger.
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LOL.
I once wrote a paper titled, "Why does the SPCA hate Schroedinger?"
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Afraid the irony will dilate your mind?
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Worst analogy ever (Score:1)
The cat example doesn't do anything to illustrate superposition of states. It's merely the quantum physics edition of "if a tree falls in the woods where nobody is watching, does it make a sound?" To which the obvious answer is yes. The cat can die of radiation in the box without you ever opening the box. The longer you wait, the more certain you can be that it's dead. That's not a superposition of states at all, it's regular garden variety uncertainty.
double slit experiment (Score:3, Interesting)
But in the double slit experiment, the act of observing the particle collapses the wave function. How is this different that putting the detector (before or) after the slit. The detector continuously monitors the decay so you are always observing whether the cat is alive or dead and is never both.
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double slit and measuring electrons power levels are two different things (and yes, most of modern physics is very trivial, but all papers and news articles leave out the sensor equipment used, causing a torrent of pundits spewing nonsense)
Re:double slit experiment (Score:4, Interesting)
I think you're missing that PART OF the dual slit experiment is that the interference bands (which occur when stuff acts like a wave) DISAPPEAR as soon as you measure which slit the stuff passes through. Interacting with the stuff (so you can measure it) causes the waveform to collapse and "be real".
And they've repeated this with photons, electrons, atoms, molecules, and large molecules. There's no reason to believe it doesn't scale up to cats and people and spaceships. It's just harder to isolate larger stuff.
How is this different that putting the detector (before or) after the slit
Damn good question. They just needed the proper lighting, with microwaves, to get the picture to be less grainy. I guess.
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Okay, the cat goes home, but the professor is shot through slits. Somebody has to do it, else we won't get flying cars and Mr. Fusion.
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FWIW this paper went into some level of depth about the sensor construction.
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De Broglieâ"Bohm Theory (Score:3)
Velocity is borked 3 ways (Score:5, Interesting)
Physics currently has 3 models of "movement".
1) The Schrodinger one, stuff jumps around according to a probability function, in all places at once, and when you measure it, you're fixing its location to one place.... often obfuscated as "collapsing the wave function" to make it sound less ridiculous. It's mathematicians solving a probability equation, swapping in known values, then being able to calculate unknowns, describe as if that's what the universe is doing when things move.
2) The classic Newtonian motion, "mass" has a property "momentum" which causes it to move in linear fashion across space. Angular momentum and momentum are separate and independent. Doesn't handle the speed of light correctly, and mass-less things still have motion, it doesn't work for those.
3) And light, it wiggles like sub atomic particles, yet it travels at some value 'c'. It interacts with matter like matter does, but it accelerates to 'c' when you stop slowing it down. Treated as if its pure energy that's oscillating and traveling somehow. Distinct from the "momentum" energy because it doesn't have mass.
Three models of motion.
Matter is made of subatomic particles, so the mode of motion must be the same for those. Light is emitted and interacts with matter and looks awfully like oscillating subatomic particles, too too coincidental.
So all three modes of motion must be the same.
Maybe you should hop in a kayak and do an oscillatory paddle across the water. Notice that when you paddle left and right, the kayak waddles left and right. But you process forwards.
Now paddle twice on the right for each once on the left, notice you're turning around? If the rotation are in sync with the oscillations, you'll also process across the water. It's a spin and translation at the same time. Take away the kayak and replace the water with the underlying resonant oscillatory field, and you have a 2D version of motion.
Its the same mechanism for light, for matter, for everything. It is limited to the range 0 to 1 wavelength W of resonance each oscillation. It has two resonance points, the stationary point, and the 1 W per oscillation one.
Look, radio waves and X-Rays cannot be travelling at the same velocity, the limit case for an electromagnetic wave has it travelling 1W per oscillation, with zero EM frequency, with zero difference between its F oscillation and the matter its interacting with 'F' oscillation, in perfect resonance and therefore zero energy difference between the light and the matter.
This gives you an experimental proof of resonance.
Xrays and radio waves travel at different velocities, all other conditions being the same. Go figure out how to measure these accurately, then you've proven resonance.
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>Xrays and radio waves travel at different velocities, all other conditions being the same. Go figure out how to measure these accurately, then you've proven resonance.
Folks have actually tried to measure the speed difference difference between different frequencies of light, and have reckoned (as far as anyone knows) that *if* there is a frequency-dependent component of the speed of light, then at most the difference can account for is something absurdly small - on the scale of 10^-15.
No discrepancy has
Then that sets F as greater than 10^30Hz (Score:1)
I have F as ~ 3.4x10^23 Hz based on your measurement of a proton size matched to the charge center of my proton in a model called [sandbox].
It's a pretty dodgy number, [sandbox] is a perfect field, it would be like absolute zero kelvin, and your proton measurement must be measured in the real world, with equipment that itself is oscillating.
This would push F up (the frequency of resonance) higher, above 10^30hz.
If you reached half the F frequency, you're be turning around in circles. You'd be a F2, the donu
What would zero EM frequency look like? (Score:1)
Maybe I can explain this more elegantly.
What would *zero* EM frequency look like?
It would look like a standing wave. At a fixed given point in space, no oscillations from the wave are experience and there is no frequency and no wavelength.
*But* you know (by observation) that matter is oscillating, electrons jiggle for example.
So zero frequency EM wave must be in motion the same as the electron it interacts with. So now our zero frequency oscillation is really oscillating the same as the electron it is inte
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Maybe I can explain this more elegantly.
What would *zero* EM frequency look like?
It would look like a standing wave.
Also known as "a stationary charge". If you have an electron sitting on your bookshelf, you have a charge/zero frequency EM wave. If you have a stationary planet, then you also have a zero frequency gravitational wave.
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I found Bohm's books in our library (he used to work in our building) and they're interesting but the fact that no one has managed to come up with a relativistic version has not helped his cause over the decades and expectations that computing power would make this tractable don't seem to have been fulfilled. But maybe no one is trying any more.
Heisenberg deliberately pushed a mystical interpretation, which Schrodinger was satirising with the Cat, and it's never really been justified IMO. It just sounds coo
Re:De Broglieâ"Bohm Theory (Score:4, Interesting)
Bohr and Heisenberg thought that QM described fundamental properties of the Universe so they choose an interpretation that made reality inherently probabilistic
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Re: How does opening box cause cat to die? (Score:3)
There's plenty of evidence for dark matter, we just don't know what it is.
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There's plenty of evidence for dark matter, we just don't know what it is.
All evidence for dark matter could also be evidence we have it wrong and are merely missing the reasons and rules to explain what has crept into the main paradigm as dark matter. It is interesting that descriptions of dark matter itself have characteristics and properties that have never been observed as properties any thing else that we know exists, nor can these characteristics or properties be explained by the top physics paradigms, like the ones we like, quantum mechanics nor solid state can explain how
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All evidence for dark matter could also be evidence we have it wrong and are merely missing the reasons and rules to explain what has crept into the main paradigm as dark matter.
The main alternative to dark matter is some kind modified gravity - the idea that we have misunderstood how gravity works on large scales.
1. Colliding galaxy clusters have been observed behaving in a way not consistent with modified gravity - the mass is not where it should be
2. One of the ways dark matter was found is by the rotational speed of galaxies - they spin too fast for the amount of matter observed, meaning there appears to be more mass than we can see. However there are some galaxies that don't
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By the way to whoever modded this funny and anyone else confused by the ambiguity, "it" refers to dark matter, not evidence. We know what the evidence is. We do not know what dark matter is.
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Can you have true randomness without quantum effects ?
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Can you have true randomness without quantum effects ?
To steal a line from WestWorld, "If you can't tell the difference, does it matter?"
Besides, this study suggest (if I read it right) that they can tell when the event is about to happen, but cannot make longer-range predictions as to when it will happen.
Uncertainty principle revisited (Score:1)
If you're trying to observe the position and velocity and spin (or orientation) of object X and your tool is a hammer of the same is greater size as X that you throw at X with high velocity, then by observing you also change its state. This is true at quantum scales and macro scales like basketballs and meteors, and is a better explanation of the uncertainty principle than the cat nonsense.
The problem with the cat is that alive and dead are mutually exclusive. A better analogy for superposition is that the
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"artificial atom"
Just how big is the atom in this article? Apparently too big to get a place on the periodic table...
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Shooting a basketball at another basketball WILL cause the targets spin and/or velocity to change so we can only obtain some information by such destructive observation techniques.
Well said!
artificial atom, what if you used a real one? (Score:1)
With a real atom would also get a sudden absence of detection photons just before a quantum jump?
Typical bad reporting (Score:5, Informative)
Opening the box to observe the cat causes it to abruptly change its quantum state randomly, forcing it to be either dead or alive. The quantum jump is the discrete (non-continuous) and random change in the state when it is observed.
Only people who don't understand quantum mechanics think it's abrupt and discontinuous. Most news stories about tests of quantum mechanics are full of confused nonsense. Even ones at sources that really ought to know better (like phys.org). The collapse of the wavefunction is a continuous process involving the buildup of decoherence as the system interacts with its environment.
Re:Typical bad reporting (Score:5, Informative)
Only people who don't understand quantum mechanics think it's abrupt and discontinuous. Most news stories about tests of quantum mechanics are full of confused nonsense. Even ones at sources that really ought to know better (like phys.org). The collapse of the wavefunction is a continuous process involving the buildup of decoherence as the system interacts with its environment.
The thing everyone seems to miss is that the Nature publication has nothing to do whatsoever with Schroedingers cat. It's about transitions in quantum energy levels, not about quantum superpositions.
Phys.org then connects the two via the "logic": cat -> cat jumps -> energy jumps, even going so far as to claim they can catch the cat mid jump. But no, they can reverse a quantum energy transition while it's going on, which is something completely different than reversing the collapse of a superposition (which is impossible).
Matter is only matter when it matters (Score:1)
Whoa whoa whoa.... matter is only matter when it matters (otherwise it exists as a waveform existing everywhere it COULD exist).... until you look at it or it interacts with the rest of the world..... .....But if you only glance at it through a sorta mirror it's still not matter? wut?
There is no superposition (Score:5, Interesting)
from Gerard 't Hooft
https://blogs.scientificameric... [scientificamerican.com]
GM: So, in this sense, superposition is a mental construct, whereas the real world doesnâ(TM)t really have that. We created a problem by our choice of this convenient tool of quantum mechanics to do our statistics for us.
GtH: Yes, thereâ(TM)s no superposition. The only superpositions are in our way of describing whatâ(TM)s going on. For very good reason: we can make transformations such that we can describe the vacuum as a single state. In reality, the vacuum is probably a very complex, fluctuating mode. If you make superpositions, you can make a single state look like the vacuum.
The Free-Will Postulate in Quantum Mechanics
https://arxiv.org/abs/quant-ph... [arxiv.org]
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Re:There is no superposition (Score:4, Funny)
This is going to ruin my Schrodinger's Physicist experiment. The one where I place a physicist in a room with a Schrodinger's cat experiment. And theorize about the state of the cat right up to the point where I open the door to observe whether or not my test subject physicist has opened the cat box. And what the state of his cat is.
Well, I have to go now. Someone is knocking on my laboratory door. I guess it's physicists all the way down.
P.S. You need to think about the implications of making a single state look like a vacuum. Vacuums scare the hell out of most cats.
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This is going to ruin my Schrodinger's Physicist experiment. The one where I place a physicist in a room with a Schrodinger's cat experiment. And theorize about the state of the cat right up to the point where I open the door to observe whether or not my test subject physicist has opened the cat box. And what the state of his cat is.
I believe this is a variant known as "Wigner's Friend [wikipedia.org]"
Misunderstands Schrödinger's Cat (Score:5, Insightful)
The summary misunderstands Schrödinger's point, which was that the cat is not both dead and alive at the same time. He was illustrating that the concept of superposition is wrong.
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No, he was illustrating that the concept of superposition is not useful on macroscopic levels.
The cat is dead (Score:2)
At some point in time it's safe to assume the cat is dead, so there is no superimposition per se.
The question is, if there's no interaction with the environment does the state even matter?
The first part is bullshit ... (Score:5, Insightful)
... because it's a thought experiment proposed by Schrödinger to mock the Copenhagen interpretation proposed by Niels Bohr and Werner Heisenberg.
The first problem is that all of the components of the experiment are classical in scale. Quantum mechanics manifests itself at the (sub) micro level.
The second problem is that it insinuates, incorrectly, that humans, by way of observation, kill or don't kill cats.
Opening the box is a "measurement." Taking a measurement is not the decision-maker. The cat is dead or it isn't. Until the condition is known, it's both, and fairly so, because of ignorance .
Appreciate that measurements happen all the time in the universe. Superposition is a natural state, and, for instance, a collision is a measurement.
The original article [nature.com] does not contain the words, "Schrödinger" or "cat."
Phys.org should have left out the first paragraph in TFS.
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Indeed, but you don't even need to open the box to know if the cat is dead or alive. Careful observation of the box itself will tell you that.
Basically the differential thermal output of a dead cat versus a live cat and you cannot beat thermodynamics is all you need to know. I can infer if the cat has died by a reduced surface temperature of the box, aka the photon's it's emitting. Looking at the emitted photons has no impact on whether the poison will be administered because they are not entangled to the r
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The original work by Schrödinger explains away or dismisses any thinking "outside the box."
Nothing can get in -- nothing can get out, including information.
Your attempts to glean clues by running experiments from without the closed system are practical, but this is a thought experiment.
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Wrong.
The steps are:
1.) Radioactive decay
2.) Geiger counter
3.) Breaking a vial
4.) Cat dies
All of those are measurements. The cat is entangled with the the radioactive nucleus.
Again, it's moot because superposition and entanglement occur at the micro level.
The experiment involves macro objects that conform to classical physics, not quantum mechanics.
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Quantum mechanics manifests itself at the micro scale. It does not at the macro.
Examples of each are behaviours of photons and baseballs.
While baseballs are easy to examine and exhibit predictable behaviour (see Houston Astros), the same is not true for photons.
Quantum experiments reveal that more than one quantum particle can exhibit the same "weirdness," as a single photon. Indeed, some atomic structures obey quantum theory and not classical physics.
Scientists are on the hunt to determine precisely where
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Fair question.
The answer, for now, borders on metaphysics (I never met a physics I didn't like).
I recall a similar situation where Einstein suggested that, in a closed system like inside an elevator, it's impossible to determine if the experience of "weight" is due to acceleration or a gravitational field.
Turns out the two phenomenon are equivalent.
--
My point is that Einstein solved a very, very, small part of a very, very large subject (General Relativity).
Knowing that acceleration and gravity are the same
smarts (Score:1)
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I get the gist of what is being said and understand some of the concepts behind it but wow.
You need to look at the math. Right now, we've made observations, and we've developed equations to model the movement. The equations are rather good. Why is it happening? No one knows that, but as long as you look at the equations, you can't go wrong.
Please think of the kittehs... (Score:1)
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who? (Score:2)
who will rewrite all those schrodinger cat jokes now?
damn science ruins everything!
Meh (Score:2)
Your credibility in any scientific context is immediately undermined when you can't spell aluminium.
Why? (Score:1)
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Because Slashdot seems to lack the ability to do even the most basic of filtering to get rid of bullshit like this. Relying on moderators to burn their mod points to knock this crap down to -1 isn't working.
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Before you read this subject line... (Score:1)
... I had simultanuously posted and not posted in this thread.
Wow, just Wow (Score:2)
deterministic (Score:2)
What the physicists didn't tell you: (Score:2)
All they need to prevent the cat from dieing is a "resurrect"-device that can turn a dead cat into a living cat.
By applying and tuning that device precisely according to measurements when the box is opened, the cat can be saved.
If rho describes the mixed state density matirix composed of projectors from possible superpositions in the Hilbert space:
( living cat )
( dead cat )
then a measurement represented by the operator O:
( Id 0 )
( 0 resurrect )
must be performed, Tr(O*rho) will then result in a
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What do you have against zombie cats ?