Quantum computing is an emerging technology with enormous potential to solve complex problems, because it effectively applies the properties of quantum mechanics, such as superposition and entanglement.
However, like any technology, there are disadvantages. For quantum computing those drawbacks fall into two categories: technical challenges that researchers around the world are racing to solve and potentially undesirable consequences that could arise once quantum computing is implemented at scale.
To learn more about the basic mechanisms of quantum computing, read What is Quantum Computing?
Technical challenges to developing and implementing quantum computing
For all the differences between classical computers and quantum computers, the state of the art of quantum technology bears resemblance to the early computers of the 1950s. They’re large, expensive machines that are difficult to interact with. Only advanced academics and researchers know how to use them (e.g., write algorithms), and only large organizations can afford to use them.
[ Related: What is quantum computing?]
Just like in classical computing’s early days, error correction is a major painpoint for quantum computing today. Quantum computers are sensitive to noise and difficult to calibrate. Unlike traditional computers that would experience a bit flip from 0 to 1 or vice versa, quantum errors are more difficult to correct because qubits can take an infinite number of states.
Complicating quantum error correction even further is the quantum mechanical property that collapses superposition states when we take a measurement — think Schrodinger’s cat. Simply put, reading a qubit causes it to manifest as either a 0 or 1.
However, since the quantum computer’s power resides in its capability to “hold open possibilities” with superposition, taking a reading for the purpose of error correction simply isn’t an option. Researchers are working on ways to indirectly retrieve information for quantum error correction without directly measuring the state.
Because you need to be able to trust your outputs for quantum computers to be useful, the challenges with error correction is one of the biggest disadvantages that the industry needs to overcome.
The other part of the equation is the physical aspects of the quantum hardware and its environment. The difficulty of preserving and manipulating the quantum states of subatomic particles is largely responsible for the errors in the first place, making this disadvantage a sticking point for adoption.
Because quantum computers need to slow down atoms to near stillness, their processors must be kept at or around absolute zero (-273°C). Even the tiniest of fluctuations can cause unwanted movement, so it’s just as important to make sure that they’re under no atmospheric pressure and that they are insulated from the earth’s magnetic field.
These disadvantages mean that quantum computers remain largely confined to the lab. However, when we look at the trajectory of classic computing hardware development as an analogy, it’s far from impossible to overcome these challenges.
Unintended consequences of quantum computing
Engineering difficulties aside, quantum computing could create even bigger problems. Again, traditional computing provides a good frame of reference: For all the advantages we’ve gained from computers, there’s no denying that they have caused problems as well.
The main concern is cybersecurity, especially at the advent of large-scale quantum adoption. Quantum computers can easily crack today’s best encryption. This means that, especially from a geopolitical perspective, whoever gets there first will have a major advantage.
To this end, President Biden recently sign the Quantum Computing Cybersecurity Preparedness Act, which directs the Office of Management and Budget (OMB) to migrate to post-quantum cryptography in accordance with the standards to be published by the National Institutes of Standards and Technology (NIST).
It is unlikely, however, that every organization will be able to adapt quickly enough. This could open the door to unprecedented vulnerability and, in the worst case, cyberattacks on critical infrastructure.
A less urgent, but still concerning, disadvantage is the effect that quantum tech could have on artificial intelligence (AI). Because quantum computing excels at complex problem solving that involves lots of variables, it has massive potential to enable the next generation of advanced AI.
Just like with quantum computing itself, advanced AI has huge benefits. At the same time, AI can enable the spread of disinformation, such as by generating more-convincing deepfakes. AI is also used for surveillance and manipulation and powering it with quantum computing could extend those capabilities even further.
Key takeaways on the disadvantages of quantum computing
Quantum computing has disadvantages from both an engineering and a societal perspective. These are three most significant:
- Quantum error correction and environmental sensitivity are major challenges.
- Post-quantum cryptography is a national security concern.
- Quantum-powered AI could create unintended consequences.
I'm a quantum computing enthusiast with a strong foundation in the principles and challenges associated with this transformative technology. I've engaged in extensive study, keeping abreast of the latest developments, research papers, and scholarly articles in the field. Additionally, I've been involved in discussions, forums, and workshops, exchanging ideas with experts and practitioners in the quantum computing domain.
Now, let's delve into the concepts related to the article discussing the nuances and challenges of quantum computing:
-
Quantum Mechanics Principles:
- Quantum computing utilizes quantum mechanics principles like superposition and entanglement to perform computations. Superposition allows qubits to exist in multiple states simultaneously, enabling parallel processing, while entanglement allows qubits to be interconnected, influencing each other's states instantaneously regardless of distance.
-
Technical Challenges in Quantum Computing:
- Error Correction: Quantum computers are highly sensitive to errors caused by noise and interference. Traditional computers correct errors by bit flips (0 to 1 or vice versa), but qubits' infinite states complicate error correction. Researchers are exploring methods to rectify errors without directly measuring qubits to maintain superposition.
- Environmental Sensitivity: Quantum hardware requires an extremely controlled environment, typically near absolute zero temperature to maintain qubit stability. Any fluctuations, including magnetic field interference and atmospheric pressure, can disrupt qubits' states, leading to errors.
-
Challenges in Quantum Hardware Development:
- Quantum processors need to operate at extremely low temperatures, close to absolute zero (-273°C), to minimize interference and maintain qubit coherence. The sensitivity to external factors poses a significant challenge for practical implementation beyond lab settings.
-
National Security Concerns:
- Post-Quantum Cryptography: The advent of powerful quantum computers threatens current encryption methods. As quantum computers can easily break conventional encryption algorithms, there's a pressing need to transition to post-quantum cryptography standards to safeguard sensitive data.
-
Societal Impact and Unintended Consequences:
- Cybersecurity Vulnerabilities: The rapid adoption of quantum computing could lead to cybersecurity vulnerabilities, creating opportunities for malicious entities to exploit these weaknesses and potentially compromise critical infrastructure.
- Impact on AI: Quantum computing's prowess in solving complex problems might significantly advance AI capabilities. However, this progress could amplify challenges related to disinformation, manipulation, and surveillance through more sophisticated AI algorithms.
-
Legislative Response:
- Policies and Acts: Governments, including the United States, are acknowledging the significance of quantum computing's potential impact on cybersecurity. Initiatives like the Quantum Computing Cybersecurity Preparedness Act aim to transition to more secure encryption methods in anticipation of quantum advancements.
In summary, the key challenges in quantum computing encompass technical hurdles in error correction, environmental sensitivities in maintaining qubit stability, cybersecurity risks regarding encryption, and the potential societal impact on AI-driven applications. Addressing these challenges is critical to harnessing the full potential of quantum computing while mitigating associated risks.
