Classical computer cannot simulate Quantum Computer
There are algorithm for QC to solve mathematical Problems which cant be solved using classcal computers
Simulation of n but system needs C0*n qubit while C0^n classical bit
The fundamental problems is the qubit states are fragile, and the gragility is a great challange
The major difficulty is to operate the system and read out the information without distroying quantum coherence
Long coherence is a major requirement among the criteria formulated by David DiVincenzo
Other criteria is system must be scalble based on elementary block- qubit
Qubit is two level system characterised by SHI> which is super position of two computional basis state 0> and 1>
Superconducting SQUID is the macroscopic quantum system which can so longer coherence
Passive line with very high quality factor at very freqeuncy shows quantum effects
Non linear device's quantum effect suppresed by dissipations. If it can work in low dissipation, quantum effect can be observed
Superconducting ring with distinct current states-flux qubits
Coulomb blockade effect with small island with distinct charge state- charge qubit
Superconducting qubits can be fabricated using standard lithograohy and thus technically scalable
With bias currrent and voltage, initial state can be controlled
Qubit shows decoherence effect to reduce coherence time.
Radiation loss at circuit lead at high frequency, act like transmission line
