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From rule based to Quantum – Journey of NLP


The field of Natural Language Processing (NLP) has come a long way since its early days of rule-based systems, where researchers used sets of hand-coded rules to analyze language to the latest developments in Quantum Natural Language Processing (QNLP), the field of NLP has undergone a remarkable transformation. It's a journey that has seen the emergence of statistical methods and deep learning techniques, allowing for more sophisticated approaches to language processing. But the introduction of quantum computing principles for NLP is arguably the most exciting development yet. With the potential to revolutionize language analysis and processing, QNLP promises to unlock the full power of human language like never before. In this blog, we'll take a deep dive into the journey of NLP and explore the groundbreaking advances that have brought us to this exciting new frontier of QNLP.

Rule-Based NLP

As we all are familiar that computers don’t understand language it understands only numbers (bits) so it was very challenging part for researchers to execute the natural language processing tasks. Rule-based NLP, also known as symbolic NLP, was one of the earliest approaches to natural language processing. This method involves creating a set of hand-coded rules that attempt to capture the grammar and syntax of a language. These rules are typically based on linguistic theories and are designed to analyze text at the sentence level. Rule-based NLP systems typically have a limited range of applications, as they rely heavily on pre-existing knowledge of a language's grammar and syntax. However, they can be useful for tasks such as text classification, named entity recognition, and information extraction. While rule-based NLP is not as widely used today as statistical or deep learning approaches, it played an important role in the early development of the field and paved the way for the more sophisticated techniques used today.

Rule-based natural language processing is a method of analyzing and processing text that uses a set of rules to determine its meaning. Rule-based NLP differs from statistical NLP in that it relies on manually created rules instead of machine learning algorithms. It's also known as semantic analysis or knowledge representation, depending on the context.

Rule-based NLP was developed during the 1970s by researchers at Stanford University and Carnegie Mellon University who wanted to create programs capable of understanding natural language without having access to large amounts of annotated data, a process called supervised learning as well as those where there wasn't enough time or money available for training models using unsupervised techniques such as clustering or dimension reduction.

Statistical NLP

Towards the end of 19th century Statistical Natural Language Processing came into existence. It is a method of language analysis that involves using statistical algorithms to process and understand human language. It relies on machine learning techniques to analyze large datasets of text and identify patterns and relationships between words and phrases.

Statistical NLP algorithms use probabilistic models to make predictions about language. According to [Razno, 2019] ML approach for the NLP task is helps to analyze text data using python libraries such as nltk, spacy etc. These models are trained on large sets of labeled data, such as text corpora, and learn to recognize patterns in the data that can be used to make accurate predictions about new, unseen text. Some common tasks that can be performed using statistical NLP include part-of-speech tagging, named entity recognition, sentiment analysis, and machine translation. Statistical NLP has become increasingly popular in recent years due to its ability to handle a wide range of language processing tasks and its effectiveness at analyzing large datasets of text.

However, one limitation of statistical NLP is that it requires large amounts of labeled training data to perform well. This can make it challenging to apply statistical NLP to languages or domains with limited data availability. Nonetheless, statistical NLP remains an important and widely used method of language processing.

Transformer & GPU for NLP

The hardware revolution with the rise of GPU’s lead to possibility of deep learning in NLP on large dataset, researchers have been able to build increasingly sophisticated models for NLP tasks such as language translation, sentiment analysis, and question answering. However, training these models can be a time-consuming and computationally intensive process. In this blog post, we'll explore the benefits of using Graphical Processing Units and cloud computing for deep learning in NLP. Comparing models such as BERT and traditional ML approach by [Gonz ́alez-Carvajal and Garrido-Merch ́an, 2020] shows that deep learning methods and use of transformers outperforms statistical methods


The whole world of NLP and language translation changed after the release of transformers with self-attention proposed by [Vaswani et al., 2017]in 2017. The introduction of the Transformer architecture in the paper was a watershed moment for the NLP community. It revolutionized the way we approach NLP tasks, allowing for faster, more accurate, and more flexible modeling of natural language. In short it understands the relation among the different words of a sentence in parallel unlike the RNN & LTM’s. Hence the name “Attention”. The impact of Transformer will undoubtedly continue to shape the direction of NLP research and development for years to come.


Deep learning models are often trained on large datasets, requiring many calculations to be performed in parallel. This is where GPUs come in. GPUs are specialized hardware devices that can perform many calculations in parallel, making them ideal for deep learning computations. Compared to traditional Central Processing Units (CPUs), GPUs can reduce training time and allow for larger models to be trained. While GPUs were once only available to researchers and organizations with access to specialized hardware, the rise of cloud computing has made GPU resources more widely accessible.

Quantum NLP

Quantum Natural Language Processing (QNLP) is a relatively new field that combines the principles of quantum mechanics with the techniques of natural language processing to analyze and understand human language in a more efficient and accurate way by taking the advantage of unique properties of quantum mechanics such as superposition and entanglement as discussed by [Di Sipio et al., 2022]. In this blog, we will explore what QNLP is, how it works, and what its potential applications, advantages and disadvantages are.

What is Quantum Natural Language Processing?

QNLP is an emerging field that explores the intersection of quantum mechanics and natural language processing. The idea behind QNLP is to use quantum computing principles to analyze and process natural language data more efficiently and accurately than traditional NLP methods. As discussed by [Ganguly et al., 2022] The origins of this field come from an abstract mathematical concept called category theory especially monoidal categories which have a diagrammatic structure. These monoidal categories have been utilized to describe various quantum mechanical phenomena in a purely pictorial fashion. When a model of natural language is equivalent to a model which explains quantum theory it signifies that QNLP is quantum-native.

How it Works?

In QNLP, words and sentences are represented as quantum states, which are combinations of different classical states. These quantum states can then be manipulated using quantum gates, which are analogous to logical gates in classical computing. By applying these gates to the quantum states representing words and sentences, QNLP algorithms can perform various NLP tasks, such as classification, clustering, and generation. [Guarasci et al., 2022]


One potential advantage of QNLP is its ability to process large amounts of data more efficiently than classical NLP algorithms. Quantum computing is well-suited for processing massive datasets due to its ability to perform many calculations in parallel. Additionally, QNLP algorithms have the potential to be more accurate than classical NLP algorithms, particularly in tasks such as sentiment analysis and machine translation.


However, there are also several limitations to QNLP. One major limitation is the current lack of quantum computing hardware that is capable of performing the calculations necessary for QNLP algorithms. While quantum computers have made significant advancements in recent years, they are still not widely available or accessible. Another limitation is the difficulty in designing and implementing QNLP algorithms. Quantum mechanics is a complex and abstract field, and applying its principles to NLP tasks requires a deep understanding of both fields.


Quantum Natural Language Processing is a promising new field that has the potential to revolutionize the way we analyze and understand human language. While QNLP is still in its early stages, it is clear that it has a wide range of potential applications in fields such as language translation, sentiment analysis, and content analysis. As quantum computing technology continues to advance, we can expect to see even more exciting developments in the field of QNLP.


[Di Sipio et al., 2022] Di Sipio, R., Huang, J.-H., Chen, S. Y.-C., Mangini, S., and Worring, M. (2022).The dawn of quantum natural language processing. In ICASSP 2022 - 2022 IEEE InternationalConference on Acoustics, Speech and Signal Processing (ICASSP), pages 86128616.

[Ganguly et al., 2022] Ganguly, S., Morapakula, S. N., and Bertel, L. G. A. (2022). An introduction to quantum natural language processing (qnlp). In Coded Leadership, pages 1–23. CRC Press.

[Gonz ́alez-Carvajal and Garrido-Merch ́an, 2020] Gonz ́alez-Carvajal, S. and Garrido-Merch ́an, E. C.(2020). Comparing bert against traditional machine learning text classification. arXivpreprint arXiv:2005.13012.

[Guarasci et al., 2022] Guarasci, R., De Pietro, G., and Esposito, M. (2022). Quantum natural language processing: Challenges and opportunities. Applied Sciences, 12(11).

[Razno, 2019] Razno, M. (2019). Machine learning text classification model with nlp approach. Computational Linguistics and Intelligent Systems, 2:71–73.

[Vaswani et al., 2017] Vaswani, A., Shazeer, N., Parmar, N., Uszkoreit, J., Jones, L., Gomez, A. N., Kaiser, L., and Polosukhin, I. (2017). Attention is all you need. Advances in neural information processing systems, 30.

Author - Hitesh Bagade

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