This 5000 qubit machine is not a universal quantum computer in the same sense of the ones being developed by other vendors. It is a quantum annealer, which can only be used to perform a few very specific calculations. It is irrelevant to bitcoin. True universal quantum computers which may be able to break elliptic curve multiplication are still a few decades away.

Even so, when we reach the stage that elliptic curve multiplication becomes vulnerable, then there are two things which can happen. One, and very simply, users can stop reusing addresses. The private key is only vulnerable once the public key is known, and the public key is only revealed when a transaction is made. If you haven't made a transaction out of an address yet, then your funds remain safe. Secondly, we can fork to create a new address type which would be quantum resistant, just like we forked to create SegWit addresses.

What do you mean needs more computing power? 1 qubit is equal to 2 bits, that is already fast. The current supercomputer will fall out of commission once quamtum computer become available. Although it is still on its cabinet computer phase this will be a breakthrough for computing power. And why think of quantum attacks of all the things? When there is a breakthrough, commercialized quantum computers will not be available for some years. Educational institutions like research, military, and aeronautics will be the first to use this just so you know. And as if low life hackers buy those quantum computers just to get into the network. That is the least thing that we should be wary of in regards to quantum computer.

Quantum computers currently do not pose any risk to Bitcoin because it would make no sense to use all those resources just to harm a cryptocurrency. In the end, we'd just fork off and all the resources they've spent would have been lost in vain.

Bitcoin will advance alonside technology. Once more powerful computers are released, the hashrate will increase as well. As soon as quantum computing becomes the norm, the hashrate will probably be high enough not to pose any risk anymore from the 51% attack perspective. Private keys may be at a high risk though, but that is something devs can fix.

I don't think anyone is stupid enough to purchase hardware worth so many millions of dollars to attempt a BTC attack when they know escaping the attack is as easy as creating a slightly improved fork.

In bitcoin, there are many other difficult problems that are still waiting for a solution. Bitcoin developers should not focus on a potential threat from non-existant sufficiently powerful quantum computers. It is better to focus on code improvements such as Schnorr signatures and Taproot, which really may help bitcoin to survive. Even if developers decided that Bitcoin should be quantum resistant, started to implement quantum resistant addresses, for instance, that would not change anything, anyway. They cannot force people, ordinary bitcoin users, to behave differently, they cannot change people's habits, they cannot forbid them to reuse addresses. People first need to learn how to use bitcoin properly in order to develop their own methods of how to protect yourself from those attack vectors and problems which can't be solved on a protocol level.

Qubits are using superposition meaning that 1 qubit is equal to 0 and 1 at the same time, much like Schrödinger's cat, qubits are technically two bits. Why would it be equal to 1 bit and be faster than the modern computers?  And yeah, entanglement is reason why qubits can hold up to two bits of data.

I said on my counter argument that it is technically 2 bits. Sorry if I do not know much about it. I am just fascinated by quantum mechanics so most things that I know is surface level. You didn't consider it in your post.

Here is the link to the one article I have read: https://superposition.com/2017/10/05/seven-things-need-know-about-qubits/


That is what I was trying to say in the first place.

Wrong, quantum-resistant cryptography has been known for decades, and it doesn't require quantum computers to work. Quantum computers aren't just more powerful classic computers, they are good for certain things, and worse at doing everything else. They aren't going to change everything, they'll just improve some fields.

Not exactly.

If we consider 3 bits, there are 8 possible combinations. 3 qubits could represent all 8 simultaneously, so would theoretically be 8 times faster.
With 4 bits, there are 16 possible combinations. 4 qubits could represent all 16 simultaneously, so would theoretically be 16 times faster.
With 5, it is 32 times.
With 6, 64 times.
And so on.

The more qubits you add, the exponential the speed increase.

Now, it's obviously not quite as simple as this. There are a huge number of other factors to consider such as getting qubits to work together, decoherence, error correction, wave collapse, etc., but the general principle is that for some specific operations (such as reversing elliptic curve multiplication) quantum computers will reduce the operations required exponentially rather than just linearly.

Excuse my ignorace, but implying we got through a soft-fork.
Does not it mean that "lost" coins might be moved again in the case of this quatum attack?

If so, it would represent an incrase of supply of BTC and in consequence its price might decrease when/if happens .