Frequently Asked Questions
To make it easy for you, we have answered few of the General questions..!
The principle of superposition states that, at any given time, every quantum state, represented by a wave function, can be expressed as a linear combination of its basis eigenstates.
The act of measurement of any observable on a wave function, which can be represented as a linear combination of its basis eigenstates, collapses the state of the wave function to one of the eigenstates.
The no-cloning theorem states that It is impossible to copy an arbitrary quantum state perfectly while leaving it unperturbed.
A qubit or a quantum bit is the fundamental quantum state representing the smallest unit of quantum information containing one bit of classical information accessible by measurement. At any given time, a two qubit system |q> can be in either |0> state or |1> state or in a superposition state of the two logical basis states |0> and|1> and can be represented as,
|q>=α|0>+β|1>, where α and β are complex values and |α|2+|β|2=1.
A binary unit of information used in classical computation is called a classical bit or simply, bit. The two possible values that it can take are 0 and 1. A qubit is the fundamental quantum state representing the smallest unit of quantum information. Unlike the classical bit, it can take values other than just |0> and |1>; it can exist in a superposition of these two logical basis states and can be expressed as ||q>=α|0>+β|1>, where α and β are complex values and |α|2+|β|2=1.
A truly random bit sequence can be defined as a sequence with all of its elements generated independent of each other, and the value of the next element in the sequence cannot be predicted, irrespective of the number of elements already produced.
There are mainly two types of random number generators:
a) Pseudo random number generator (PRNG): Devices that produce random numbers from a deterministic algorithm are called pseudo random number generators.
b) True random number generator (TRNG):True random number generators measure some unpredictable, or at least, difficult to predict physical processes and use the results to create a sequence of random numbers. The process of collecting unpredictable data is called ‘entropy gathering’.
Quantum random number generators (QRNGs) make use of the inherent unpredictable behaviour of any quantum measurements. The measurement outputs are truly random given that the input state is a superposition of its basis eigenstates.
Randomness is a probabilistic property; that is, the properties of a random sequence can be characterized and described in terms of probability. A number of statistical tests can be applied to a given sequence to check for its randomness or non-randomness. The likely outcome of statistical tests, when applied to a truly random sequence, is known a priori and can be described in probabilistic terms. There are an infinite number of possible statistical tests, each assessing the presence or absence of a “pattern” which, if detected, would indicate that the sequence is non-random. Because there are so many tests for judging whether a sequence is random or not, no specific finite set of tests is deemed “complete.”