Shake to measure
Measure the singlet state
Follow the previous section on entanglement to create the singlet state, which should show a rainbow pattern on the surface of the qubits. The rainbow pattern is meaningful, and we will cover it later. For now, just know that the rainbow means that the qubits are entangled.
To leave the singlet state, make a measurement. Jab either Qubi in any direction. You should now see that each Qubi has a small white light on it. These are unentangled quantum states.
Look at where they land. If you hold them so that the buttons and charging ports are aligned, the two will always face opposite directions. This is the definition of the singlet state!
Definition
Singlet state: the entangled state where measuring either qubit causes the other qubit to "collapse" to the opposite side.
Note that when either Qubi is measured, entanglement ends. Entanglement is a consumable resource, consumed by measurement.
The axis matters, not the direction
Measurement is an operation that depends only on the axis you are shaking on. The axis matters, not the direction. Shaking up is the same as shaking down. Shaking north is the same as shaking south.
The jab can be in any direction. By default, the Qubi snaps to a small set of possible axes: X, Y, Z, and the diagonal axes between those.
Calibrating the jab
- Jab in a straight line, in any direction.
- Make sure you aren't twisting the Qubi or curving the trajectory.
Included in:Qubi Quickstart