Browse Definitions:
Definition

quantum computer

A quantum computer is a machine, as-yet hypothetical, that performs calculations based on the behavior of particles at the sub-atomic level. Such a computer will be, if it is ever developed, capable of executing far more millions of instructions per second (MIPS) than any previous computer. Such an exponential advance in processing capability would be due to the fact that the data units in a quantum computer, unlike those in a binary computer, can exist in more than one state at a time. In a sense, the machine "thinks" several "thoughts" simultaneously, each "thought" being independent of the others even though they all arise from the same set of particles.

Engineers have coined the term qubit (pronounced KYEW-bit) to denote the fundamental data unit in a quantum computer. A qubit is essentially a bit (binary digit) that can take on several, or many, values simultaneously. The theory behind this is as bizarre as the theory of quantum mechanics, in which individual particles appear to exist in multiple locations. One way to think of how a qubit can exist in multiple states is to imagine it as having two or more aspects or dimensions, each of which can be high (logic 1) or low (logic 0). Thus if a qubit has two aspects, it can have four simultaneous, independent states (00, 01, 10, and 11); if it has three aspects, there are eight possible states, binary 000 through 111, and so on.

Quantum computers might prove especially useful in the following applications:

  • Breaking ciphers
  • Statistical analysis
  • Factoring large numbers
  • Solving problems in theoretical physics
  • Solving optimization problems in many variables

The main difficulty that the research-and-development engineers have encountered is the fact that it is extremely difficult to get particles to behave in the proper way for a significant length of time. The slightest disturbance will cause the machine to cease working in quantum fashion and revert to "single-thought" mode like a conventional computer. Stray electromagnetic fields, physical movement, or a tiny electrical discharge can disrupt the process.

This was last updated in June 2010

Continue Reading About quantum computer

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • internal audit (IA)

    An internal audit (IA) is an organizational initiative to monitor and analyze its own business operations in order to determine ...

  • pure risk (absolute risk)

    Pure risk, also called absolute risk, is a category of threat that is beyond human control and has only one possible outcome if ...

  • risk assessment

    Risk assessment is the identification of hazards that could negatively impact an organization's ability to conduct business.

SearchSecurity

  • security information and event management (SIEM)

    Security information and event management (SIEM) is an approach to security management that seeks to provide a holistic view of ...

  • polymorphic virus

    A polymorphic virus is a harmful, destructive or intrusive type of malware that can change or 'morph,' making it difficult to ...

  • cyberterrorism

    According to the U.S. Federal Bureau of Investigation, cyberterrorism is any 'premeditated, politically motivated attack against ...

SearchHealthIT

  • accountable care organization (ACO)

    An accountable care organization (ACO) is an association of hospitals, healthcare providers and insurers in which all parties ...

  • patient engagement

    Patient engagement is an ideal healthcare situation in which people are well-informed about -- and motivated to be involved -- in...

  • personal health record (PHR)

    A personal health record (PHR) is a collection of health-related information that is documented and maintained by the individual ...

SearchDisasterRecovery

  • business continuity and disaster recovery (BCDR)

    Business continuity and disaster recovery (BCDR) are closely related practices that describe an organization's preparation for ...

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

SearchStorage

SearchSolidStateStorage

  • hybrid hard disk drive (HDD)

    A hybrid hard disk drive is an electromechanical spinning hard disk that contains some amount of NAND Flash memory.

Close