![]() Here, we provide estimates on the performance of one of these codes.Ī very promising class of quantum error correcting codes are topological codes. Hence, one of the main challenges for achieving a universal quantum computer is the development of techniques, known as quantum error correcting codes, to protect quantum information against errors. Such quantum computers are, however, vulnerable to noise from the environment or imperfect hardware, as this destroys the coherence of the quantum states used in computations. Experiments are only now getting good enough to actually put all these ideas to the test.The use of quantum states for computing purposes will enable computations that are intractable for classical computers, such as the simulation of quantum many-body systems. They have even studied how the process of quantum error correction can work when it's subject to the same errors as the quantum information it's trying to protect. ![]() Researchers have been studying quantum error correction since the mid-1990s, and they've learned all kinds of things along the way: how to manipulate encoded qubits without having to unencode them and how error-prone qubits are allowed to get before everything falls apart. Some quantum codes are like two copies of the classical code above wrapped up into one, and others involve exotic new states of matter that researchers have only barely caught a glimpse of in the lab. Quantum codes borrow this same basic idea but with the goal of protecting against all of the extra errors that a qubit is subject to. Storing: Now it takes many bit flips to change from 000000000 to 111111111, which is a rarer event. But once encoded, it becomes much harder for the environment to corrupt the information you’re When stored on its own, a single bit can easily be corrupted by the environment: It takes just a single bit flip to change a 0 to a 1. The idea is that you are encoding the information of one qubit into a few qubits.Ī simple way to encode an ordinary bit is to represent a 0 as many 0s (000000000) and a 1 as many 1s (111111111). The word "code" here doesn't have anything to do with secret codes. ![]() There are many ways to spread the information of one qubit among many, and scientists call these choices quantum error correcting codes. This kind of poking around never tells you enough to reveal the quantum state of the encoded qubit and destroy all those precious quantum properties. Although measuring quantum states normally dissolves some of their quantumness, the measurements made in quantum error correction are carefully crafted to reveal just enough information to diagnose errors. The way to spot this qubit rot is through measurement. Qubits are much more freewheeling, and they are subject to-quite literally-infinitely more errors. But in that case, there’s really only one type of error that can occur: a 0 can flip to a 1 and vice versa. There’s a name for this ruthless destruction of all things quantum: This can erode a delicate superposition relatively quickly, and things only get worse the more atoms you add. So although one atom on its own is a pretty ideal quantum-y thing, as soon as you put it next to other atoms (like you would in a quantum computer), the whole mess starts jostling around. This heat, mild as it may be, makes quantumness melt away. Why not? Because our bodies, and basically everything we encounter, are sitting at the relative inferno that we call room temperature. You can’t really see a quantum superposition in action or grab hold of quantum entanglement. Our everyday experiences demonstrate this inherent fragility of quantum objects. ![]() A tiny bit of light here, a sporadic vibration there-pretty much anything is enough to disrupt the inner workings of a quantum computer. The problems get compounded when scientists try to sprinkle in superposition and entanglement, both of which are necessary for quantum computing. Unfortunately, they are kind of fussy, like pets that insist on ignoring your commands. Qubits (a mashup of quantum and bits), store and process information inside of a quantum computer. All of the quantum pieces they're made of are-how can we put this delicately?-extraordinarily fragile. Small prototypes already exist, but they all have a problem: They are really finicky. Quantum computers are special purpose machines full of promise and, these days, quite a bit of hype. Back to all entries Quantum Error Correction Quantum computers need some help when things go wrong. ![]()
0 Comments
Leave a Reply. |