Efficient classical database operations are crucial for modern data processing and data management tasks. At the same time, quantum computing algorithms may offer a substantial speed-up for certain computational use cases. Quantum systems allow access to superposition and entanglement, enabling quantum parallelism and the use of interference. We define a quantum database state [8, 9] as an indexed superposition state as given, e.g., by the state returned by a quantum random access memory call (see [3, 4]). The database state is assumed to be located in the central quantum processing unit of a quantum computer. We investigate the feasibility of transferring general classical database operations to the quantum domain, with indices in superposition.
Efficient classical database operations are crucial for modern data processing and data management tasks. At the same time, quantum computing algorithms may offer a substantial speed-up for certain computational use cases. Quantum systems allow access to superposition and entanglement, enabling quantum parallelism and the use of interference. We define a quantum database state [8, 9] as an indexed superposition state as given, e.g., by the state returned by a quantum random access memory call (see [3, 4]). The database state is assumed to be located in the central quantum processing unit of a quantum computer. We investigate the feasibility of transferring general classical database operations to the quantum domain, with indices in superposition.
Databases are an essential component of modern computing infrastructures and allow efficient manipulation of inherently structured data. The structure depends on the type and relationships of the individual data elements and on the access pattern. Extending the concept of databases to the quantum domain is expected to increase both the storage efficiency and the access parallelism through quantum superposition. In addition, quantum databases may be seen as the result of a prior state preparation ready to be used by quantum algorithms when needed. On the other hand, limiting factors exist and include entanglement creation, the impossibility of perfect copying due to the no-cloning theorem, and the impossibility of coherently erasing a quantum state. In this work, we introduce quantum databases within the broader context of data structures using classical, or more precisely cloneable, and quantum data and indexing. In particular, we are interested in quantum databases' practical implementation and usability, focusing on the definition of the basic operations needed to create and manipulate data stored in a superposition state. Specifically, we address the case of quantum indexing in combination with cloneable data. For this scenario, we define the operations for database preparation, extension, removal of indices, writing, and read-out of data, as well as index permutation. We present their algorithmic implementation and highlight their advantages and limitations. Finally, we introduce the next steps toward defining the same operations in the more general context of quantum indexing and quantum data.
Quantum computers are proven to be more efficient at solving a specific class of problems compared to traditional digital computers. Superposition of states and quantum entanglement are the two key ingredients that make quantum computing so powerful. However, not all quantum algorithms require quantum entanglement (e.g., search through an unsorted database). Is it possible to utilize classical wave superposition to speed up database searching as much as by using quantum computers? There were several attempts to mimic quantum computers using classical waves. It was concluded that the use of classical wave superposition comes with the cost of an exponential increase in resources. In this work, we consider the feasibility of building classical wave-based devices able to provide fundamental speedup over digital counterparts without the exponential overhead. We present experimental data on database searching through a magnetic database using spin wave superposition. The results demonstrate the same speedup as expected for quantum computers. Also, we present examples of numerical modeling demonstrating classical wave interference for period finding. This approach may not compete with quantum computers with efficiency but outperform classical digital computers. We argue that classical wave-based devices can perform some of the quantum algorithms with the same efficiency as quantum computers as long as quantum entanglement is not required.
This paper investigates the potential of leveraging quantum state superposition to optimize database queries. Traditional database queries often face bottlenecks due to sequential processing and limitations in parallelization. We propose a novel approach that translates database queries into quantum state superposition problems, enabling parallel exploration of multiple query branches simultaneously. The core mechanism involves constructing a quantum circuit designed to exploit superposition and implementing algorithms for efficient result merging. We present a theoretical framework and a conceptual algorithm demonstrating the feasibility of this approach, highlighting the potential for significant speedups in query execution. The focus is on the conceptual design and theoretical considerations, without requiring experimental validation. The key innovation lies in directly mapping database query operations onto quantum superposition and leveraging quantum parallelism. This work represents a foundational step toward exploring quantum computing's role in database optimization.
Manipulating a database system on a quantum computer is an essential aim to benefit from the promising speed-up of quantum computers over classical computers in areas that take a vast amount of storage and processing time such as in databases. In this paper, the basic operations for manipulating the data in a quantum database will be defined, e.g. INSERT, UPDATE, DELETE, SELECT, backing up and restoring a database file. This gives the ability to perform the data processing that usually takes a long processing time on a classical database system, in a simultaneous way on a quantum computer. Defining a quantum version of more advanced concepts used in database systems, e.g. the referential integrity and the relational algebra, is a normal extension to this work
Manipulating a database system on a quantum system is an essential aim to benefit from the promising speed-up of quantum computers over classical computers in areas that take a vast amount of storage and processing time such as in databases. In this paper, the basic operations for manipulating the data in a quantum database will be defined, e.g. INSERT, UPDATE, DELETE, SELECT, backing up and restoring a database file. This gives the ability to perform the data processing, that usually takes a long processing time on a classical database system, in a simultaneous way on a quantum system. Defining a quantum version of more advanced concepts used in database systems, e.g. the referential integrity and the relational algebra, is a normal extension to this work.
With the development of quantum computing, significant advancements have been made since the 1980s, leading to the birth of quantum computers and sparking widespread enthusiasm in this emerging field. While quantum computing is still in its early stages of development, researchers are increasingly drawn to its magic power and have identified numerous compelling applications across various domains, ranging from cryptography, query optimization, and machine learning. Notably, one of the most promising applications lies within the realm of database management systems, giving rise to quantum computing for databases, which holds the potential to offer substantial advantages over classical databases, particularly in terms of query processing speed and efficiency, as well as saving memory space. This vision paper aims to provide an overview of the current research challenges and opportunities of quantum computing for the field of databases, as well as outline the potential for the development of a quantum multi-modal database.