J. Philippe Blankert, 28 February 2025, author@blankertbooks.com and info@bqm.ai
Abstract
Quantum computing is emerging as a powerful technology, and organizations face a choice between using Quantum as a Service (QaaS) – accessing quantum computers through the cloud – or owning a quantum computer on-premises. Each approach has distinct advantages and disadvantages, both at a high level and in technical terms. The best choice often depends on an organization’s goals, resources, and industry-specific requirements. Below, we analyze QaaS versus owning a quantum computer, covering cost, scalability, security, and more, with examples across finance, cryptography, scientific research, healthcare, and other sectors.
Advantages of Quantum as a Service (QaaS)
Cost Efficiency (OpEx vs. CapEx)
QaaS minimizes upfront investment by allowing pay-per-use or subscription access to quantum hardware. Businesses avoid spending millions on purchasing exotic quantum equipment and building specialized facilities. Instead, they pay operational expenses for only the quantum time and resources they need. This is a major cost advantage – for example, IBM’s cloud quantum services let users run small experiments for as little as a few dollars (https://www.ibm.com/quantum), whereas owning a quantum computer can cost tens of millions up front (https://www.dwavesys.com). By eliminating capital expenditure, QaaS lowers the barrier to entry. Small startups, academic labs, and R&D teams can experiment with quantum algorithms without a huge financial gamble (https://www.quantinuum.com). In contrast, only large institutions (governments, big tech or finance firms) might afford an on-premise quantum system. QaaS thus democratizes access, making quantum computing exploration cost-effective for a broad range of industries (https://www.research.ibm.com/quantum).
Scalability and Latest Hardware Access
QaaS offers on-demand scalability – users can request more quantum bit (qubit) resources or try larger devices as they become available, without having to upgrade any hardware themselves. As newer generations of quantum processors come online, cloud providers integrate them, so customers automatically get access to cutting-edge performance (https://aws.amazon.com/braket). For instance, Amazon Braket and Azure Quantum regularly add new quantum backends (superconducting, ion-trap, photonic, etc.), enabling users to scale up problem sizes or switch to more qubits as needed (https://www.microsoft.com/en-us/quantum). This means a research team can start with a small device and seamlessly move to larger ones or specialized architectures as their needs grow. On-premises ownership, by contrast, is limited to the machine purchased – if technology advances (e.g., a new 1000-qubit device is released), the owner must invest in an upgrade or be stuck with older hardware.
Ease of Use and Maintenance-Free Operation
Quantum hardware is notoriously delicate – superconducting qubits, for example, require ultra-low temperatures and isolation from noise. Maintaining such a system demands specialized engineers and constant calibration. QaaS relieves users of this burden: the cloud provider handles all maintenance, calibration, and infrastructure (cryogenics, vacuum systems, etc.). From the user’s perspective, the quantum computer is simply an API or web interface. This makes adoption much easier, since no in-house quantum hardware expertise or facilities are required (https://www.dwavesys.com). Businesses and developers can focus on writing quantum algorithms rather than keeping a machine running.
Integration with Classical Cloud Resources
Most quantum algorithms today run in a hybrid manner – a classical computer pre/post-processes data and coordinates calls to the quantum processor. QaaS is typically offered by major cloud platforms (Amazon, Microsoft, IBM, etc.), making it easy to integrate quantum computing with classical computing services. Users can leverage the cloud’s classical compute, storage, and AI services alongside quantum calls in a unified workflow (https://aws.amazon.com/braket).
Disadvantages of Quantum as a Service (QaaS)
Data Privacy and Regulatory Compliance
A primary concern with cloud-based quantum computing is data security and privacy. Sending data (especially sensitive data) over the internet to an external quantum service can violate regulatory or internal privacy requirements. Industries like healthcare and finance are bound by strict regulations (e.g., HIPAA in healthcare, GDPR in Europe, banking secrecy laws) that may prohibit certain data from leaving on-premises systems or require strong safeguards (https://www.ibm.com/quantum).
Latency and Network Dependency
Cloud access inherently introduces network latency. Quantum computing tasks today are often short (taking milliseconds or less on the QPU), but the round-trip communication time to the cloud can be much longer, especially if iterative hybrid algorithms are running (https://www.dwavesys.com). An on-premise quantum computer could be directly connected to local systems with sub-millisecond latency, whereas a cloud quantum call could take seconds or more end-to-end due to internet overhead and queue times.
Limited Customization and Control
When using QaaS, users are constrained by the hardware and software configurations the provider offers. They cannot modify the quantum hardware or its low-level firmware – you get a black-box service. Owning the machine gives full control: you decide who can use it, when, and how it’s configured (https://www.quantinuum.com).
Advantages of Owning a Quantum Computer
Full Control over Hardware and Software
When an organization owns a quantum computer, it has complete control over how that machine is used. The company decides scheduling, prioritization of jobs, and can ensure the quantum processor is always available for its needs (no multi-tenant sharing) (https://www.research.ibm.com/quantum).
No External Dependency or Vendor Lock-In
By having an on-premises quantum computer, organizations remove dependence on third-party providers. This avoids the vendor lock-in problem entirely – you’re not tied to a specific cloud service’s APIs or pricing (https://www.dwavesys.com).
Disadvantages of Owning a Quantum Computer
Extremely High Upfront and Operational Costs
The most obvious drawback to owning a quantum computer is cost. Quantum hardware and its support systems are extremely expensive. Current state-of-the-art quantum computers (like superconducting or ion-trap systems) cost on the order of millions of dollars to build or purchase (https://www.dwavesys.com).
Maintenance Complexity and Specialized Workforce Requirements
Running a quantum computer is not like running an ordinary server. It requires a highly specialized workforce – quantum physicists, engineers, and technicians – to maintain and operate the system. Issues can arise daily: qubits decohere, calibrations drift, components fail at cryogenic temperatures, etc., and troubleshooting these requires deep expertise (https://www.quantinuum.com).
Conclusion
Both Quantum as a Service and owning a quantum computer have vital roles to play, and in many cases they complement each other. Today, QaaS is the dominant model – it offers flexibility, low cost to experiment, and rapid access to the latest quantum innovations (https://www.research.ibm.com/quantum). Owning a quantum computer is currently rare, undertaken by organizations with very specific needs for control, security, or continuous use that justify the expense and effort. It provides unmatched sovereignty and customization at the price of high complexity.
By understanding the advantages and disadvantages of each approach, stakeholders can make informed decisions and position themselves to benefit from this quantum revolution.