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A primer on quantum computing storage and memory

Quantum computing storage and memory are quite different from traditional storage. The implications for storage capacity, for example, are extraordinary.

In 2017, Microsoft surprised attendees of its flagship Ignite conference when the company revealed its first quantum computer. Since that time, quantum computing has been steadily gaining momentum, so storage admins need to take note.

Even so, quantum computing is a work in progress -- there are still a number of challenges that the technology must overcome. Many of these challenges pertain to memory and data storage.

The role of quantum memory in storage

Quantum computers cannot use conventional memory and data storage -- they must instead use quantum memory. Quantum memory is more capable than conventional memory but is also fragile and error-prone.

Quantum memory is based on quantum bits, or qubits. Quantum bits are vastly different from the bits that conventional computers use. Typical computers use a system of binary bits that can reflect a value of either zero or one. Quantum bits can store a zero or a one, but thanks to a concept called superposition, they can also contain zero and one at the same time. It is essentially a form of multidimensional storage.

Quantum computing is a work in progress -- there are still a number of challenges that the technology must overcome. Many of these challenges pertain to memory and data storage.

The main advantage of quantum memory is that it can store vast amounts of information, in the form of various states. To put this into prospective, 100 bits of conventional storage would accommodate a mere 12.5 bytes of data. However, 100 quantum computing storage bits could contain more states than all of the world's hard drives combined, according to Doug Finke of Quantum Computing Report in a presentation at the 2021 Storage Developer Conference.

However, quantum memory storage is nonpersistent. While classical memory, i.e., RAM, is also nonpersistent, RAM stores data until a device powers down or reboots. Conversely, quantum memory can only store data for about 100 milliseconds (ms).

It is also impossible to read a quantum state without altering it in the process. Additionally, users can only read the data once. Reading the data causes the quantum bit to release all the states it has stored -- at that point, the quantum bit simply reflects a value of either zero or one.

Chart of quantum vs. classical computing

The possibilities of quantum computing storage

Since quantum bits can only store data for a fraction of a second, there are no quantum hard drives.

However, quantum computing is ideal for solving complex mathematical problems. Solving such problems almost always requires multiple steps; the results of one step serve as input for the next step. Quantum bits can work for such a task as long as the computational processes outpace the rate of data decay. In other words, if the technology can read and process data in 50 ms, then it does not matter that the data essentially evaporates after 100 ms.

Likewise, the idea that users cannot read quantum bits without significantly altering them in the process is appealing to security professionals. After all, simply being able to read data in quantum bit storage guarantees that no one else has accessed the data. Some theorize that it may be possible to build a quantum network that enables data to be sent from point to point with a guarantee that there has been no tampering.

Quantum memory and quantum computing have many other security implications. For instance, quantum computing will make it possible to break encryption algorithms that are too complex for a classical computer to break. In the case of a ransomware infection, an organization that has access to a quantum computer may be able to decrypt its data without having to pay the ransom. However, a quantum computer may make it possible to create next-generation encryption algorithms that current technology cannot break.

How close are we to a payoff?

Quantum memory has improved significantly in reliability over the last few years, but more work is still necessary. The best quantum memory available today is estimated to be about 85% reliable. As such, error correction and quantum memory efficiency need improvements.

It seems likely that developers will solve such problems in the next few years, which will make quantum memory more practical than it is today.

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