I’m referring to the real world engineering problem that interconnection requirements scale exponentially with the number of qubits. There simply isn’t enough volume to make it work beyond an upper threshold limit of qubits, since they also have to be quite close to each other.
It’s not at all been proven what this upper limit is or that it allows for capabilities matching or exceeding the average human brain.
If the size is scaled down to reduce the distances another problem arises in that there’s a maximum limit to the amount of power that can be supplied to any unit volume, especially when cryogenic cooling is required, as cooling and refrigeration systems cannot be perfectly efficient.
Something with 1/100th the efficiency of the human brain and the same size might work, i.e. 2kW instead of 20 watts.
But something with 1/1000000 the efficiency of the human brain and the same size would never work. Since it’s impossible for 20MW of power to be supplied to such a concentrated volume while cooling away the excess heat sufficiently. That is a hard thermodynamic limit.
There is the possibility of the qubits being spread around quite a bit farther from each other, i.e. in a room-size space, but that goes back to the first issue as it brings exponentially increasing losses, from such things as signalling issues. Which may be partially mitigated by improvements from such things as error correcting codes. But there cannot exist a ‘complete’ solution.
As perfectly lossless information transmission is only an ideal and not achievable in practice.
I’m referring to the real world engineering problem that interconnection requirements scale exponentially with the number of qubits. There simply isn’t enough volume to make it work beyond an upper threshold limit of qubits, since they also have to be quite close to each other.
It’s not at all been proven what this upper limit is or that it allows for capabilities matching or exceeding the average human brain.
If the size is scaled down to reduce the distances another problem arises in that there’s a maximum limit to the amount of power that can be supplied to any unit volume, especially when cryogenic cooling is required, as cooling and refrigeration systems cannot be perfectly efficient.
Something with 1/100th the efficiency of the human brain and the same size might work, i.e. 2kW instead of 20 watts.
But something with 1/1000000 the efficiency of the human brain and the same size would never work. Since it’s impossible for 20MW of power to be supplied to such a concentrated volume while cooling away the excess heat sufficiently. That is a hard thermodynamic limit.
There is the possibility of the qubits being spread around quite a bit farther from each other, i.e. in a room-size space, but that goes back to the first issue as it brings exponentially increasing losses, from such things as signalling issues. Which may be partially mitigated by improvements from such things as error correcting codes. But there cannot exist a ‘complete’ solution.
As perfectly lossless information transmission is only an ideal and not achievable in practice.