Quantum correction with three codes (original) (raw)
Digital System Design for Quantum Error Correction Codes
Quantum computing is a computer development technology that uses quantum mechanics to perform the operations of data and information. It is an advanced technology, yet the quantum channel is used to transmit the quantum information which is sensitive to the environment interaction. Quantum error correction is a hybrid between quantum mechanics and the classical theory of error-correcting codes that are concerned with the fundamental problem of communication, and/or information storage, in the presence of noise. e interruption made by the interaction makes transmission error during the quantum channel qubit. Hence, a quantum error correction code is needed to protect the qubit from errors that can be caused by decoherence and other quantum noise. In this paper, the digital system design of the quantum error correction code is discussed. ree designs used qubit codes, and nine-qubit codes were explained. e systems were designed and configured for encoding and decoding ninequbit error correction codes. For comparison, a modified circuit is also designed by adding Hadamard gates.
Introduction to quantum error correction
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1998
Quantum states are very delicate, so it is likely some sort of quantum error correction will be necessary to build reliable quantum computers. The theory of quantum error-correcting codes has some close ties to and some striking differences from the theory of classical error-correcting codes. Many quantum codes can be described in terms of the stabilizer of the codewords. The stabilizer is a finite Abelian group, and allows a straightforward characterization of the error-correcting properties of the code. The stabilizer formalism for quantum codes also illustrates the relationships to classical coding theory, particularly classical codes over GF(4), the finite field with four elements.
Simulating the Effects of Quantum Error-correction Schemes
It is important to protect quantum information against decoherence and operational errors, and quantum error-correcting (QEC) codes are the keys to solving this problem. Of course, just the existence of codes is not efficient. It is necessary to perform operations fault-tolerantly on encoded states because error-correction process (i.e., encoding, decoding, syndrome measurement and recovery) itself induces an error. By using simulation, this paper investigates the effects of some important QEC codes (the five qubit code, the seven qubit code and the nine qubit code) and their fault-tolerant operations when the error-correction process itself induces an error. The corresponding results, statistics and analyses are presented in this paper.
2016
In this paper, we provide an implementation of five, seven and ninequbits error correcting codes on a classical computer using the quantum simulator Feynman program. We also compare the three codes by computing the fidelity when double errors occurs in a depolarizing channel. As triple errors and more are considered very unlikely, it has negligible effect on the next results.
Quantum Error Correction Methods
2016
This study surveys the mathematical structure of a quantum error correcting codes and the way they are developed through certain stages of error correction. In particular, the families of Calderbank-Shor-Steane codes (CSS) and the stabilizer codes are discussed and through elaborative examples it will be shown that the CSS codes are in the family of the stabilizer codes. Since the study of the CSS codes depends on a firm knowledge of classical coding theory, a rigorous mathematical review of the linear codes is done separately. Analysing the structure of the stabilizer formalism is highly depended on the effective use of some group theoretic notions. This structure is discussed in more detail and examples will be given. As the ultimate application of the quantum error correction the rules of the fault-tolerant quantum computing is explored and finding the threshold condition of an example will be done.
Experimental Implementation of a Concatenated Quantum Error-Correcting Code
Physical Review Letters, 2005
Concatenated coding provides a general strategy to achieve the desired level of noise protection in quantum information storage and transmission. We report the implementation of a concatenated quantum error-correcting code able to correct against phase errors with a strong correlated component. The experiment was performed using liquid-state nuclear magnetic resonance techniques on a four spin subsystem of labeled crotonic acid. Our results show that concatenation between active and passive quantum error correcting codes offers a practical tool to handle realistic noise contributed by both independent and correlated errors.
Quantum Error Correction (QEC) is a rigorous consolidation of facts and figures from both quantum mechanics and classical theory of error correcting codes aimed for a stronger output in the quantum domain. Here, we achieve correcting multiple bit-flip or phase-flip errors using a three-qubit quantum code with an extra qubit. Furthermore, for the first time, we construct a three-qubit full quantum error-correcting code that corrects errors not only on one qubit but multiple qubits. We then extend this approach in order to construct a six-qubit full quantum multiple error-correcting code. The quantum cost is significantly reduced as compared to any existing full quantum error-correcting code.
Entanglement increases the error-correcting ability of quantum error-correcting codes
Physical Review A, 2013
If entanglement is available, the error-correcting ability of quantum codes can be increased. We show how to optimize the minimum distance of an entanglement-assisted quantum error-correcting (EAQEC) code, obtained by adding ebits to a standard quantum error-correcting code, over different encoding operators. By this encoding optimization procedure, we found several new EAQEC codes, including a family of [[n, 1, n; n − 1]] EAQEC codes for n odd and code parameters [[7, 1, 5; 2]], [[7, 1, 5; 3]], [[9, 1, 7; 4]], [[9, 1, 7; 5]], which saturate the quantum singleton bound for EAQEC codes.
Theory of quantum error-correcting codes
Physical Review A, 1997
Quantum Error Correction will be necessary for preserving coherent states against noise and other unwanted interactions in quantum computation and communication. We develop a general theory of quantum error correction based on encoding states into larger Hilbert spaces subject to known interactions. We obtain necessary and sufficient conditions for the perfect recovery of an encoded state after its degradation by an interaction. The conditions depend only on the behavior of the logical states. We use them to give a recovery operator independent definition of error-correcting codes. We relate this definition to four others: The existence of a left inverse of the interaction, an explicit representation of the error syndrome using tensor products, perfect recovery of the completely entangled state, and an information theoretic identity. Two notions of fidelity and error for imperfect recovery are introduced, one for pure and the other for entangled states. The latter is more appropriate when using codes in a quantum memory or in applications of quantum teleportation to communication. We show that the error for entangled states is bounded linearly by the error for pure states. A formal definition of independent interactions for qubits is given. This leads to lower bounds on the number of qubits required to correct e errors and a formal proof that the classical bounds on the probability of error of e-error-correcting codes applies to e-errorcorrecting quantum codes, provided that the interaction is dominated by an identity component.
Benchmarking Quantum Computers: The Five-Qubit Error Correcting Code
Physical Review Letters, 2001
The smallest quantum code that can correct all one-qubit errors is based on five qubits. We experimentally implemented the encoding, decoding and error-correction quantum networks using nuclear magnetic resonance on a five spin subsystem of labeled crotonic acid. The ability to correct each error was verified by tomography of the process. The use of error-correction for benchmarking quantum networks is discussed, and we infer that the fidelity achieved in our experiment is sufficient for preserving entanglement.