en:this_little_thing_called_qubit
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en:this_little_thing_called_qubit [2021/01/09 20:29] jaddawyn [What is a qubit ?] |
en:this_little_thing_called_qubit [2021/01/16 10:29] (current) |
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| ==== What is a qubit ? ==== | ==== What is a qubit ? ==== | ||
| Classic bits are based on voltage associated to binary level 0 or 1, while qubits are based on quantum states.\\ | Classic bits are based on voltage associated to binary level 0 or 1, while qubits are based on quantum states.\\ | ||
| - | A qubit is a particle and has 2 base states noted |0> and |1> (called Dirac notation, we'll see that in detail later). As a quantum particle, it is in superposed state before being read. Like the cat that is both dead and alive while you open the box.\\ | + | \\ |
| + | A qubit is a particle and has 2 base states noted |0> and |1> (called Dirac notation, we'll see that in detail later). As a quantum particle, it is in superposed state before being read. Like the cat that is both dead and alive before | ||
| \\ | \\ | ||
| Let's come back to the previous experiment: | Let's come back to the previous experiment: | ||
| - | {{ :quantumcomputing:electron_cat.gif }} | + | {{ :en:1_particle.png?400 |}} |
| + | \\ | ||
| + | When the particle leaves the source it is in superposed state: i.e. a probability combination of |0> and |1>. When it comes to the detector, decoherence happens and the particle collapses to a fixed state |0> or |1>. | ||
| + | \\ | ||
| + | \\ | ||
| + | But manipulating qubits alone is quite useless. But the same way we can group bits into sets, qubits can be grouped into **registers**.\\ | ||
| + | A quantum register is a set of several qubits we will use for computing. | ||
| + | \\ | ||
| + | \\ | ||
| + | You must wonder what is the point of qubits since we get 0 or 1 in the end like bits... all is about probabilities in the middle. Be patient we'll see that later. | ||
| + | \\ | ||
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| - | When the particle leaves the source it is in superposed state: i.e. |0> and |1> at the same time. When it comes to the detector, it collapse and get a fixed state |0> or |1>. | + | |
| + | <columns 100% 50% -> | ||
| + | Previous: [[en: | ||
| + | < | ||
| + | ;;# | ||
| + | Next: [[en: | ||
| + | ;;# | ||
| + | </ | ||
en/this_little_thing_called_qubit.1610220586.txt.gz · Last modified: 2021/01/16 10:29 (external edit)
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