Many proposals exist for the implementation of quantum error correction. A popular approach is to compute with sets of entangled physical qubits, called 鈥渓ogical qubits鈥, that enable the detection and correction of errors without breaking quantum physics鈥 rules about measurement and how it affects systems.
Copying quantum information is not possible due to the no cloning theorem. In classical computers, error correction often employs redundancy: for example, if you duplicate each bit 10 times then it is easy to detect and correct a single bit flip. To get around the no cloning theorem in quantum error correction you can spread the (logical) information of one logical qubit onto a highly entangled state of several (physical) qubits. .
Working with entangled units of qubits also allows one to circumvent quantum mechanics鈥 measurement problem: when a qubit is measured, its delicate quantum information is collapsed into a specific state and the richness of information is lost, therefore, one must measure the errors and not the qubits themselves.