What is Measurement-Based Quantum Computation?
Measurement-based quantum computing (MBQC) is a model of quantum computation where a universal set of operations can be performed by making adaptive single-qubit measurements on an entangled resource state, known as the cluster state. This approach contrasts with gate-based models that use sequences of unitary gates to manipulate qubits.
In MBQC, the cluster state is prepared first and then measured adaptively based on the outcomes of previous measurements. The sequence of measurements effectively performs a quantum computation by manipulating the entanglement structure within the resource state.
How Does It Work?
In a 2D cluster-state, qubits are arranged in a lattice with each qubit entangled to its nearest neighbors. The key idea is that measurements on these qubits can be used to perform quantum computations without the need for complex gate operations. Each measurement collapses the state of one qubit and changes the entanglement structure of the remaining qubits, leading to a chain reaction of entanglement consumption.
The adaptive nature of MBQC means that the sequence of measurements is determined by the outcomes of previous measurements, allowing for flexible and powerful computation.
Why Does It Matter?
Measurement-based quantum computing offers a different approach to building scalable quantum computers. Unlike gate-based models which require precise control over many qubits simultaneously, MBQC can be more robust against certain types of errors and may be easier to implement in some physical systems.
Moreover, the resource state in MBQC can be prepared in advance, potentially allowing for faster computation times compared to gate-based models where gates need to be applied sequentially.
Real-World Applications
Measurement-based quantum computing has potential applications in areas such as cryptography, optimization problems, and simulation of complex systems. For instance, MBQC can be used to solve certain types of optimization problems more efficiently than classical computers.
Additionally, the ability to perform computations using a resource state that is prepared once and then measured adaptively makes it particularly suitable for tasks where error correction is challenging.
Frequently asked questions
What are cluster states in quantum computing?
Cluster states are two-dimensional arrays of entangled qubits used as a resource state in measurement-based quantum computation. Each qubit is entangled with its nearest neighbors, forming a complex network that can be manipulated through adaptive measurements.
How does MBQC differ from gate-based quantum computing?
In MBQC, computations are performed by making adaptive single-qubit measurements on an entangled resource state. In contrast, gate-based quantum computing uses sequences of unitary gates to manipulate qubits, often requiring precise control over many qubits simultaneously.
Can measurement-based quantum computation be used for error correction?
Yes, while MBQC can be more robust against certain types of errors compared to gate-based models, it still requires careful consideration and implementation of error correction techniques. The adaptive nature of measurements can sometimes make error correction simpler in some scenarios.
What are the advantages of using a 2D cluster state over other resource states?
A 2D cluster state provides a structured entanglement network that is easier to visualize and manipulate. It also allows for more straightforward implementation of certain quantum algorithms, making it a popular choice in MBQC.
Try it live
Everything above runs in your browser — open Cluster-State Quantum Computer 2D: Measurement-Based Computing and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.
▶ Open Cluster-State Quantum Computer 2D: Measurement-Based Computing simulation