Physical and logical qubits
In quantum computing, a qubit is a unit of information analogous to a bit (binary digit) in classical computing, but it is affected by quantum mechanical properties such as superposition and entanglement which allow qubits to be in some ways more powerful than classical bits for some tasks. Qubits are used in quantum circuits and quantum algorithms composed of quantum logic gates to solve computational problems, where they are used for input/output and intermediate computations.
Cubic field
A cubic field is called a pure cubic field, if it can be obtained by adjoining the real cube root formula_2 of a cubefree positive integer "n" to the rational number field Q. Such fields are always complex cubic fields since each positive number has two complex non-real cube roots.A cyclic cubic field "K" is its own Galois closure with Galois group Gal("K"/Q) isomorphic to the cyclic group of order three. However, any other cubic field "K" is a non-galois extension of Q and has a field extension "N" of degree two as its Galois closure. The Galois group Gal("N"/Q) is isomorphic to the symmetric group "S" on three letters.