9
votes
Accepted
Do quantum loops exist?
It depends what you mean by "loop".
Nielsen and Chuang are referring to loops like the ones that appear in an SR latch. Wires literally running backwards to earlier in the circuit, creating ...
- 30.1k
8
votes
Does Google's error correction paper invalidate Gil Kalai's arguments?
Note: views are my own.
I think experiments of this type will refute Gil's arguments, but I would be uncomfortable claiming that yet. I like nice clear don't-even-really-need-statistics answers to ...
- 30.1k
7
votes
What is entropy quantum computing?
I've never heard about "entropy quantum computing" before. Both the links you provided only give extremely generic information, mostly devoid of details, together with rather bold claims. A ...
glS♦
- 21.7k
5
votes
Accepted
Why are quantum systems fabricated to be anharmonic?
Superconducting qubits are a type of quantum resonator. They are fabricated to be anharmonic so that the energy difference $\hbar \omega_{01}$ between the two lowest levels $|0\rangle$ and $|1\rangle$ ...
- 1,215
5
votes
Does Google's error correction paper invalidate Gil Kalai's arguments?
Noise
"Does Google's error correction paper invalidate Gil Kalai's arguments?"
The only thing that will invalidate Gil Kalai's arguments, is an actual experiment that demonstrates quantum ...
- 12.8k
3
votes
Accepted
Checking if Explanation of Quantum Computer is Correct
It’s a first step but you might have gotten off the rails at the end.
Taking it line by line:
A quantum computer uses physical phenomenon to perform operations called gates.
Sure, this is fine. ...
3
votes
Accepted
Quantum and DNA computing
The NMR quantum computing implementation you mentioned used cytosine as a 2-qubit platform because cytosine has two adjacent, carbon-bound hydrogen atoms with slightly different hyperfine couplings ...
- 1,215
2
votes
Accepted
Why can two atoms can be entangled?
If you have already accepted that qubits can be entangled, then you can see that atoms can be entangled too by realizing that we can encode qubits into atoms. We can do this by selecting a pair of ...
- 19.1k
2
votes
Can the paper by Monz et al. (2015) be regarded as a real implementation of Shor's algorithm?
It's fundamentally not possible to demonstrate "scalable" factoring by doing $n=15$. If the approach was so scalable, it should have actually scaled up and done larger numbers!
In my opinion,...
- 30.1k
2
votes
Accepted
Changing the phase of one qubit is equivalent to changing the phase of another qubit. What is the physical interpretation of this?
The underlying idea here is that the global phase of quantum state doesn't matter and is unobservable. For example with the state $e^{i\theta}|01\rangle$ you mentioned, if you measure it in any ...
- 1,215
2
votes
Accepted
Physical interpretation of a 2-photon-qubit system occupying the antisymmetric Bell state
The confusion here arises because of not being careful about what the labels inside the kets mean.
When we talk about the Bell states (or about the phenomena of entanglement), we consider two ...
- 1,058
1
vote
Physical interpretation of a 2-photon-qubit system occupying the antisymmetric Bell state
You're exactly right that indistinguishable bosons are represented by symmetric states. However, when we think about a photons in QIS, we often think about them interacting with beamsplitters. When a ...
- 1,215
1
vote
Accepted
Hamiltonian in CNOT gate implementation
The total Hamiltonian $\hat{H}$ is written as the sum of the following three terms:
$$
\hat{H}_1 = \frac{\hbar \omega_1}{2} \hat{\sigma}_{z1} \otimes \hat{I}
$$
$$
\hat{H}_2 = \hat{I} \otimes \frac{\...
- 1,320
1
vote
what is the elementary Lab devices (and their specifications) for building superconducting qubits?
I'm not an expert of superconducting qubits, but I work around some. A non-exhaustive list of what you would need includes:
Some sort of photolithography system to create patterns for the structures ...
- 1,215
1
vote
Accepted
Could a “disco ball” be a good geometry for trapped ion quantum computers?
Visually this looks cool, but there are two big reasons this kind of geometry isn't feasible. These reasons hold true even if you could somehow figure out an ion trap that gives you a perfect ...
- 406
1
vote
Could a “disco ball” be a good geometry for trapped ion quantum computers?
Very interesting concept! I'm not a trapped ion expert, but few concerns that immediately come to my mind to think through are two-qubit gates, small spatial perturbations cascading, and practicality.
...
- 1,215
1
vote
Accepted
Using entropy quantum computing for solving optimization problems
Based on advice by gIS I looked for quantum reservoir engineering. In short, it is a technique allowing to stabilize certain quantum state $\mathcal{S}$ with engineered coupling to an environment $\...
- 13.1k
Only top scored, non community-wiki answers of a minimum length are eligible