- #1
Mk
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Yeah so, scientists in Japan have the CNOT gate, control not. What does it do? What's the truth table... other stuff. Are gates made of transistors?
In summary, the CNOT gate is a reversible gate that flips the second bit if the first is 1. It is used in quantum information technology to perform a NOT on the second bit if the first bit is set to 1.
- #2
chroot
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Science Advisor
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Could you please provide some context? I have no idea what you're talking about.
- Warren
- Warren
- #3
cronxeh
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http://strc.herts.ac.uk/tp/info/areas/qip/qu_gates.html
This relates to qubits and quantum information theory i suppose
This relates to qubits and quantum information theory i suppose
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- #4
marlon
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chroot said:
Mk, is talking about Quantum-Information-Technology, chroot. The CNOT gate is one of them reversible gates, and it is also named the reversible XOR-gate. Basically the gate flips the second bit if the first is 1 and does nothing if the first bit is zero (hence the name controlled-not).
This gate performs a NOT on the second bit if the first bit is set to 1 and it performs a copy-operation if the second bit is initially set to 0.
The problem is that all these one-bit and twobit gates are non-universal, they cannot compute any operation using just the gate in question. The "first" universal gate is the three-bit Toffoli-gate or the controlled-controlled-NOT-gate.
It computes : (x,y,z) ---->(x,y,z + xy) where the sum is the sum modulo 2
This gate performs all the operations (NAND, COPY) necessary to be universal...
regards
marlon
- #5
Mk
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marlon said:
Thanks a lot. Exactly what I needed... but I'm not sure about the CNOT is the XOR. XOR aka EOR (eyore, the donkey!), is eXclusive OR. XOR gives a true if either A and B but not both, are true.
- #6
marlon
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The CNOT gate is just the same as the reversible XOR-gate
regards
marlon
regards
marlon
- #7
Mk
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Ahhh! I see. 
FAQ: CNOT Gate: What is it & How Does it Work?
What is a CNOT gate?
A CNOT gate, also known as a controlled-NOT gate, is a two-qubit quantum logic gate that is used to perform an operation on two qubits simultaneously.
How does a CNOT gate work?
A CNOT gate works by flipping the state of the target qubit (the second qubit) if and only if the control qubit (the first qubit) is in the state |1>. If the control qubit is in the state |0>, the target qubit remains unchanged.
What are the inputs and outputs of a CNOT gate?
The inputs of a CNOT gate are two qubits: the control qubit (the first qubit) and the target qubit (the second qubit). The output of a CNOT gate is the resulting state of the two qubits after the operation is performed.
Can a CNOT gate be used on more than two qubits?
No, a CNOT gate can only be performed on two qubits at a time. However, multiple CNOT gates can be applied in sequence to perform operations on more than two qubits.
What is the significance of the CNOT gate in quantum computing?
The CNOT gate is a fundamental gate in quantum computing and is used in many quantum algorithms. It is particularly useful in creating entanglement between qubits, which is essential for performing quantum operations such as teleportation and superdense coding.