Introduction to Quantum ML
Quantum machine learning (Quantum ML) is a field of study that combines quantum computing principles with machine learning techniques. It aims to improve the performance of machine learning algorithms by utilizing the unique properties of quantum systems, such as superposition and entanglement. Two examples of quantum machine learning are using quantum computers to perform optimization tasks that are difficult for classical computers and using quantum algorithms to analyze large data sets more efficiently. However, it is still an active research area, with many proposed approaches still in the theoretical stage.
Understanding Quantum Data
Quantum data is any data source in a natural or artificial quantum system. This could be data generated by a quantum computer, such as the samples gathered from the Sycamore processor for Google’s demonstration of quantum supremacy. Quantum data exhibit superposition and entanglement, resulting in joint probability distributions that could require an exponential amount of classical computational resources to represent or store. The quantum supremacy experiment demonstrated that it is possible to sample from a highly complex joint probability distribution of 253 Hilbert space.
NISQ processors generate noisy quantum data typically entangled just before the measurement. Models can be created using heuristic machine learning techniques that maximize the extraction of useful classical information from noisy entangled data. The TensorFlow Quantum (TFQ) library provides primitives for developing models that disentangle and generalize correlations in quantum data, allowing for improving existing quantum algorithms and discovering new quantum algorithms.
Advantages of Quantum ML
Quantum machine learning (QML) combines the power of quantum computing with machine learning techniques to solve problems that would be infeasible or impractical to solve using traditional methods. Some of the potential advantages of QML include:
- Speedup: For certain tasks, such as large-scale data classification and feature selection, quantum algorithms, such as the quantum version of support vector machines, can provide exponential speedups over classical algorithms.
- Improved optimization: Quantum computing can find global optima more efficiently than classical methods for multidimensional, non-convex cost functions, which can be helpful for model training and tuning hyperparameters.
- Enhanced representation: Quantum states can provide a richer set of features for representing data than classical states, improving performance for tasks such as image and speech recognition.
- Increased security: Quantum-based methods can enhance machine learning security against adversarial attacks, including transmitting quantum keys.
More benefits are
- Improvements in run-time: obtaining faster results.
- Learning capacity improvements: increase of the capacity of associative or content-addressable memories.
- Learning efficiency improvements: less training information or simpler models are needed to produce the same results, or more complex relations can be learned from the same data.
Classical vs Quantum ML: Key Differences
Classical machine learning algorithms are based on mathematical optimization and probability theory and train models that can make predictions or decisions based on input data. Examples include decision trees, support vector machines, and neural networks. These algorithms search for patterns in the data and use these patterns to make predictions. Quantum machine learning algorithms, on the other hand, are based on quantum mechanics and are used to train models that can make predictions or decisions based on quantum states.
These algorithms take advantage of the unique properties of quantum mechanics, such as superposition and entanglement, to perform impossible calculations with classical algorithms. Examples of quantum machine learning algorithms include quantum neural networks, quantum support vector machines, and quantum principal component analysis. Overall, the main difference between classical and quantum machine learning algorithms is the underlying mathematical framework they are based on and the types of calculations they can perform. While classical algorithms are based on classical physics and are limited by the computational resources available, quantum algorithms are based on quantum physics and can potentially perform certain calculations exponentially faster than classical algorithms.
Challenges in Quantum ML
Quantum machine learning (QML) is a relatively new field that combines the power of quantum computing with machine learning capabilities. However, several obstacles and limitations are currently impeding the development and practical application of QML.
- Lack of large-scale quantum computers: The main challenge for QML is the need for large-scale quantum computers. Current quantum computers are in their early stages of development and can handle only a limited number of qubits (quantum bits). As a result, most QML algorithms can only be executed on small-scale quantum computers, limiting their practical applications.
- Lack of understanding of quantum algorithms: QML is based on quantum algorithms, which still need to be discovered. This makes it difficult to design and develop efficient QML algorithms that fully exploit quantum computing’s unique properties.
- Noisy quantum devices: Quantum devices are extremely sensitive to noise and errors, which can lead to errors in QML algorithm results. The “noise problem” is one of quantum computing’s most significant limitations.
- Limited availability of quantum software and libraries: There needs to be more quantum software and libraries for QML; implementing QML algorithms is difficult for researchers and practitioners.
- Lack of standardization: QML is still in its early stages, and the algorithms and techniques must be more standardized. This makes comparing and evaluating different QML approaches difficult.
Despite these obstacles and limitations, QML remains an active area of research, with numerous ongoing efforts to overcome them. As large-scale quantum computers are developed and our understanding of quantum algorithms grows, QML is likely to become a more practical and powerful tool for solving complex problems in the future.
Quantum ML in Industry
Various industries, including finance, healthcare, and energy, can benefit from quantum computing. Some specific use cases of quantum computing in the enterprise include:
- Drug Discovery: Molecular simulations with quantum computing can speed up the discovery of new drugs.
- Financial modelling: Using quantum computing to solve complex financial models and optimize portfolios is possible.
- Supply Chain Optimization: Quantum computing can optimize logistics and transportation in supply chain management.
- Cybersecurity: Using quantum computing, new, more secure encryption technologies can be developed and used to break prevalent encryptions.
- Energy: Quantum computing can help reduce environmental impact by optimizing the design and operation of energy systems like power grids and batteries.
- Machine Learning: Quantum computing can train and run machine learning models on massive data.
Quantum ML: Key Insights
Data availability profoundly changes the question when assessing the capabilities of quantum computing to aid in machine learning. In our work, we create a practical set of tools for investigating these concerns, which we then use to create a new projected quantum kernel method with several advantages over prior approaches. We progress towards the largest numerical demonstration of potential learning advantages for quantum embeddings to date, 30 qubits. While a comprehensive computational advantage in a real-world application needs to be observed, this research lays the groundwork for the future. We invite any interested readers to read the paper as well as the accompanying TensorFlow-Quantum tutorials, which make it simple to build on this work.
