Marisol reads that banks are testing message links that reveal any eavesdropper, and that a new kind of computer handles certain problems far faster than an ordinary one. Both machines run on ideas from this topic.
Superposition, measurement's single definite outcome, and the Heisenberg uncertainty principle have left the lab. This lesson names technologies built on them.
A quantum computer stores information in superpositions of states. An ordinary computer's memory holds each piece of information as one definite thing at a time; a quantum computer's storage can be in several states at once.
Why that storage helps with certain problems is beyond this course. The quantum part to recognize is the storage itself: superpositions of states.
Quantum-based cybersecurity uses measurement's rule. A measurement produces a single definite outcome, and it changes a superposition into one definite state.
An eavesdropper cannot read a message's quantum carriers without measuring them, and measuring them disturbs their states. The receiver's checks find the changed states, so eavesdropping shows up.
The Heisenberg uncertainty principle sets limits that technology has to work within: no instrument, however well built, can pin down both a quantum object's position and its momentum exactly at once.
A quantum computer is said to store information in superpositions of states. What does that mean, in this topic's words?
A superposition is one quantum object in several of its quantum states at once.
An ordinary memory element is always in one definite condition; a quantum computer's storage element can be in several at once.
Reading the storage is a measurement, so a single definite outcome appears when the machine's answer is read.
It means the computer's storage elements are quantum objects held in several states at once until they are read.
A bank's quantum-secured link is tapped by an eavesdropper. How does the tapping show up?
The message rides on quantum carriers whose states the sender prepares.
Reading the carriers is a measurement, and a measurement produces a definite outcome and changes a superposition into one definite state.
The receiver's checks find states that no longer match what the sender prepared.
The eavesdropper's measurements change the carriers' states, and the mismatch gives the tapping away.
What does a quantum computer store information in?
In a quantum-secured message link, what gives an eavesdropper away?
Jocasta says: 'The Heisenberg uncertainty principle sets a limit that no improved instrument can beat.' Is Jocasta correct?
Which technology stores information in superpositions of quantum states?
A quantum-secured link reveals eavesdroppers. Which statement gives the reason?
Which of the following is an example of the Heisenberg uncertainty principle limiting a technology?