What is a barrier to entry preventing quantum computing?

The immense complexity behind quantum computing

Quantum computing is based on the principles of quantum mechanics, which govern the behavior of matter and energy on the atomic and subatomic levels. Building a quantum computer requires manipulating individual atoms and photons to create quantum bits (qubits) that can exist in a superposition of 0 and 1 simultaneously. This enables quantum computers to perform calculations exponentially faster than classical computers in certain applications.

However, controlling qubits and maintaining delicate superpositions of states require advanced physics and engineering. Quantum effects quickly break down due to interference from the external environment. This makes scaling up to large numbers of logical qubits incredibly difficult. The immense complexity behind quantum mechanics is the primary barrier preventing widespread adoption of quantum computing.

Barrier to Quantum Computing

Extreme precision needed in qubit fabrication and control

Qubits must be precisely fabricated and controlled to very fine tolerances to maintain quantum coherence. Most qubit technologies require cryogenic temperatures close to absolute zero to minimize interference. However, this introduces vibrations that cause qubits to destabilize over time. Engineers must fine-tune systems to attenuate vibrations while scaling up qubit counts into the hundreds or thousands.

Delicate pulse sequences must also correctly manipulate qubits during algorithmic operations. A single mistake can cause the quantum state to decohere and calculations to fail. Equipment must facilitate high fidelity qubit control for extended durations to run quantum algorithms successfully. Achieving this level of precise qubit manipulation is highly complex and challenging.

Lack of error correction in existing quantum computers

Noise from vibrations, electromagnetic waves, defects, and other interference frequently causes qubit quantum states to destabilize and errors to accumulate. Existing quantum computers lack robust error correction, which is essential for running complex algorithms reliably. Some types of errors can cascade, causing calculations to fail in seconds.

Quantum error correction codes can detect and correct certain errors. However, this requires many additional qubits solely for error detection. The overhead grows exponentially as algorithms become more complex. For example, estimates indicate reliable million qubit computers may require billions of physical qubits. Developing advanced error correction is critical for usable quantum computing.

Qubit performance metrics across different qubit types

Superconducting vs Trapped Ion

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Limits on maximally entangling large numbers of qubits

Many quantum algorithms rely on multi qubit entanglement to gain exponential speedups. However, creating large entangled states remains an immense challenge. Quantum entanglement linking hundreds or thousands of qubits has yet to be demonstrated experimentally. Technical limits constrain the number of qubits that can be entangled simultaneously before fidelity rapidly decays.

Most existing quantum computers can only create entanglement between two, three or small numbers of qubits at once. Generating massive quantum entanglement requires new breakthroughs in qubit connectivity, control, and error correction. Overcoming limits on entanglement is a pivotal obstacle on the path to complex quantum computing.

Need for advanced algorithms, applications and training

While quantum hardware remains highly limited, developing algorithms, applications and training programs significantly lags behind. Relatively few software developers and researchers have quantum computing and programming experience. New breakthroughs and tools for simplified programming are essential to increase adoption once more capable quantum computers release.

Currently, only a small number of quantum algorithm frameworks exist, mainly focused on chemistry, optimization, and machine learning. Myriad other application areas remain untapped. Expanded research into quantum algorithms and training programs will be critical to deliver demonstrable quantum advantage across industries when hardware matures. Building a robust quantum ecosystem is key.

High financial investment with unclear commercial viability

Major technology companies and startups have invested billions of dollars into quantum computing research over the past decade. However, commercially viable quantum computers likely remain years away. Uncertainty persists around when quantum computers will surpass classical systems at valuable applications. This ambiguous timeline makes securing additional financing and investments more difficult across the quantum industry.

Continued substantial funding is imperative to drive rapid progress in overcoming complex hardware and software challenges. Developing larger, more reliable quantum computers currently requires an intensive capital expenditure with an undetermined return on investment. Convincing stakeholders to continually provide financing remains an obstacle for quantum computing development.

Strict regulatory controls on quantum technology exports

Because quantum computing has major national security implications, governments worldwide impose strict export controls on quantum technology sales. For example, cold atoms and superconducting qubits are listed as sensitive technologies with trade restrictions. Companies building quantum hardware and software must adhere to complex regulations that limit foreign sales and distribution.

Navigating export laws across different countries is an intricate legal and compliance challenge. Startups and universities aiming to attract international talent or collaborate globally get entangled in regulatory complexities. Laws intended to protect national security ultimately hamper rapid innovation pipelines in quantum information science. Alleviating this burden can accelerate advancement.

Limited interoperability between early quantum hardware

Dozens of quantum computing hardware startups and academic labs are racing to build systems. However, no standards currently exist across the industry. Each company and university team is individually developing proprietary technology stacks. This fragmentation creates “quantum islands” where systems cannot interoperate and exchange information.

Absence of common standards also restricts compatibility with classical hardware and limits toolsets for interfacing with quantum processors. Extensive custom engineering is required to bridge distinct quantum islands. Developing universal standards for controlling, programming and linking quantum systems will maximize development productivity as the technology scales.

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Scarcity of a robust quantum supply chain and infrastructure

Very few vendors supply specialized components needed to construct quantum computers, including cryostats maintaining extremely cold temperatures. Consumers battle over limited inventory, inflating costs and delaying project timelines. Many custom parts uniquelly manufactured for individual teams lack replacements if damaged.

Expanding manufacturing capabilities across the entire quantum stack is necessary to fuel innovation among startups and enterprises. Shared foundry services for developing superconducting qubits, photonic systems and other constituents could empower new entrants. Constructing a dynamic quantum infrastructure with accessible tools will cultivate a thriving ecosystem.

Limited knowledge development opportunities in quantum

Extremely few universities offer robust quantum computing engineering and science programs compared to traditional computer science curriculums. Students lack exposure to quantum information concepts early in their education. Mastering the interdisciplinary skills needed across physics, mathematics, computer science, and engineering poses steep learning curves for graduates and professionals.

Most online quantum computing resources remain surface level, while advanced coursework requires access to costly lab equipment and technology. Broadening accessible education channels for students and professionals to gain practical quantum knowledge will expand talent pools available to support technology commercialization when quantum computers approach viability.

Public misconceptions about capabilities of quantum computers

Widespread media exposure surrounding quantum computing frequently overhypes capabilities of existing machines. The public assumes quantum computers can already break all modern cryptography and revolutionize industries overnight. However, publicly available quantum devices remain exceptionally noisy and unstable. Misinterpreting the reality of this highly experimental technology erodes trust and expectations longer term.

Managing anticipation by conveying realistic timeframes for impact as quantum computers incrementally improve can align perceptions. The community must take care to accurately represent current accomplishments while also noting remaining challenges to increase public understanding and steer policies as the technology gradually matures over the next decade.

Insufficient incentives for tech talent to enter quantum computing

Quantum computing salaries remain below compensations offered across mature technology sectors, even as demand for engineers and researchers with quantum expertise intensifies. After dedicating years towards specialized graduate degrees, students get enticed away by major tech companies providing lucrative packages and stable corporate environments.

Startups struggle retaining talent against FAANG recruiters, government labs, defense agencies, and other established organizations wooing pioneers away. To prevent a brain drain, academia and industry must expand pathways for entering the quantum workforce and offer competitive incentives on par with classical computing to anchor the next generation of talent.

Risk of optimizing quantum hardware that becomes obsolete

We remain distant from full scale fault tolerant quantum computers. Current noisy intermediate scale quantum (NISQ) devices use fragilie qubits unsuited for error correction. Teams worldwide are racing down unique technological tracks towards disparate qubit modalities. However, breakthroughs may disrupt the landscape and render some early strategic bets obsolete.

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Investing deeply into technological corners that hit dead ends could divert vital resources away from alternate approaches that succeed long term. While pushing performance boundaries now accelerates scientific understanding, widespread incremental improvements on existing qubits may offer diminishing returns if paradigms shift. The field must balance innovating rapidly today while keeping options open.

Difficulties convincing enterprises to prepare meaningfully for quantum

Many business leaders hesitate allocating substantial budgets towards quantum computing initiatives with limited short term value generation and unclear timelines showing return on investment. However, organizations risk falling behind rivals by delaying meaningful preparations for the coming quantum era.

As hardware progresses, companies proactively running encryption upgrades, simulation testing, algorithm development and staff training will outpace competitors operationally unready when quantum capabilities arrive. Convincing management on launching comprehensive strategies today for longer term resilience remains an obstacle across risk averse industries.

Global competition introducing economic and political pressures

Intense international competition in quantum computing intersects rising geopolitical tensions among major powers. As quantum R&D plays a pivotal role in future global influence, friction across national interests threatens collaboration vital for technological progress. Clashing country priorities also pressure researchers balancing contributing to open science while securing competitive advantages.

Navigating escalating rhetoric regarding how quantum computing bears on economic or military supremacy grows more complex each year. Maintaining constructive alliances across borders will help the field advance swiftly by sharing knowledge and avoiding bifurcation into isolated blocs working against mutual betterment.


In summary, while no single challenge blocks the pathway towards scalable, fault-tolerant quantum computers, the technology must overcome a mosaic of hardware, software, financial, regulatory, educational and geopolitical obstacles in the years ahead. Continued patience, persistence and global cooperation both within the quantum community and across the public and private sectors will drive progress addressing each barrier, bringing this revolutionary computing paradigm to fruition.


What is the biggest technological obstacle facing quantum computing currently?

The lack of error correction in existing quantum computers is the largest technical barrier. Uncorrected errors cause quantum calculations to fail before completing, limiting the potential of quantum algorithms. Developing practical error correction remains critical.

How much investment has gone into quantum computing research so far?

Over the past decade, tech giants, startups, governments and universities have invested more than $25 billion collectively into quantum computing R&D to date across hardware, software and education programs according to estimates.

When will quantum computers become commercially viable?

Most experts predict commercially valuable quantum computing is still 10-15 years away at the earliest. Incremental hardware improvements must continue addressing errors, scalability limits and other challenges before quantum computers clearly offer advantages exceeding classical supercomputers at valuable applications.

Can quantum computers already break all modern encryption?

No. Currently available quantum computers remain exceptionally unstable and cannot yet run Shor’s algorithm to crack encryption. Significant hardware upgrades incorporating error correction are first needed before exhibiting cryptanalytic potential.

What industries will first adopt quantum computing?

Chemistry, finance, optimization and machine learning are likely the first sectors applying quantum computing for commercial uses as algorithms mature. However, a wide span of industries should ready today to fully capitalize on quantum capabilities as computers scale up over the next decade.