Today is World Quantum Day. It is celebrated on April 14, a reference to 4.14, the rounded first digits of Planck’s constant, which describes the behavior of particles and waves at the atomic level, including the particle aspect of light.

World Quantum Day is a bottom-up initiative of a global network of scientists, engineers, educators, communicators, entrepreneurs, technologists and their institutions. Its main goal is to advance the public’s understanding of what could be the next big thing in scientific research and its applications.

Just like other next big things, the promise of quantum computing, communication and sensing is generating venture capital funds, government investments, R&D investment by large companies and many start-ups. Here’s a quick rundown of where it’s going, where it is today, and how we got here.

**The future of all quantum things **

Five quantum system developers have announced plans to have fault-tolerant quantum computing hardware by 2030, and many industry watchers believe that by then we will see a clear quantum advantage for a range of applications such as drug discovery.

To get a sense of where quantum will be in the near future, I’ve been conducting a survey of a number of experts over the past few days, asking them for their predictions on the key quantum-related advances over the next five years. Here are the results:

dr Celia Merzbacher, Executive Director, The Quantum Economic Development Consortium (QED-C): “There are many areas where advances related to quantum computing are needed and made. One that I believe will be particularly important is quantum error correction, which is essential to unlocking the full potential of quantum computing.”

Doug Finke, Managing Editor, Quantum Computing Report: “The next five years of quantum computing will be the era of NISQ [Noisy Intermediate-Scale Quantum] machine and we will see more and more powerful NISQ machines being introduced. Although there may be some applications that use these to gain quantum advantage, most potential quantum applications still will not find these NISQ engines powerful enough to outperform classical computational solutions. However, at the end of the five-year period, we will see the emergence of error-corrected, fault-tolerant quantum processors, and this will be the tipping point for the large-scale deployment of quantum computing in real-world applications.”

David Awschalom, Liew Family Professor of Molecular Engineering and Physics at the University of Chicago, Principal Investigator at Argonne National Laboratory, Director of the Chicago Quantum Exchange and Director of Q-NEXT, a Department of Energy center for quantum information science: “In the In the next In five years, we expect the emergence of entangled quantum networks in metropolitan areas for secure communication. These networks can also be used to create small clusters of quantum machines for advanced computing. We also believe that quantum sensors will be used to significantly improve clocks, mapping and intracellular sensing.”

Itamar Sivan, Co-Founder and CEO of Quantum Machines: “I believe that the most important advance in quantum computing in the next five years will be the availability of quantum accelerators that can be used as seamlessly as GPUs are today. Increasing availability will lower the bar on accessibility, take quantum computing from niche to mainstream, and allow applications to easily benefit from quantum technologies, including improving financial modeling, vastly improving computational chemistry, and more.”

Nir Minerbi, Co-Founder and CEO of Classiq Technologies: “The most important advance in quantum computing by 2027 is probably beyond our imagination. In the 1970s, if you asked someone what you could do with billions of transistors on a chip, the answer was probably “a powerful calculator” and not “use a Google search” or “the internet in your pocket”. While the key outcome of the quantum paradigm shift in computing is still unknown, or perhaps not even invented, by 2027 we will have incredibly powerful quanta if we can ensure quantum software advances hand-in-hand with hardware computers that power materials science that would revolutionize carbon capture, supply chain optimization and therapeutic discovery. That’s one of the reasons I’m so excited to be part of this industry today.”

**The state of quanta today**

Most of the funding for quantum-related research comes from the public sector. China announced plans to invest $15 billion in quantum computing, the European Union $7.2 billion, the US $1.3 billion, the UK $1.2 billion, and India and Japan each $1 billion US dollars.

The private sector is becoming increasingly involved. According to McKinsey, investment in quantum computing startups has exceeded $1.7 billion in 2021, more than double what it was in 2020. The number of pure-play software startups is growing faster than any other segment of the quantum computing market.

A recent Capgemini survey of executives found that 23% are working or planning to use quantum technologies. One in ten expects quantum computing to be available for use in at least one major application within three years. 28% of companies surveyed by quantum software startup Zapata said they have allocated a budget of $1 million or more for quantum investments. 69% of companies surveyed say they have adopted quantum computing or plan to do so in the next year. Quantum adopting companies are preparing on multiple fronts: 51% identify talent/build internal team; 49% experiment and create proofs of concept; 48% conduct experiments with quantum hardware or simulators; and 46% create new applications.

**Milestones in Quantum Mechanics**

41 years ago, Nobel laureate Richard Feynman argued that “nature isn’t classical, damn it, and if you want to do a simulation of nature you’d better do it quantum mechanically,” a statement later seen as a rallying cry for the development of a quantum computer . Here are (somewhat randomly) important milestones in the history of quantum mechanics.

1900 German theoretical physicist Max Planck proposes that radiant energy is not emitted continuously but in discrete packets called quanta.

1905 Albert Einstein extends Planck’s hypothesis to explain the photoelectric effect—shine of light on certain materials can serve to liberate electrons from the material—and proposes that light itself is made up of individual quantum particles, or photons.

1924 The term quantum mechanics is used for the first time in a work by Max Born.

1925 Werner Heisenberg, Max Born and Pascual Jordan formulate matrix mechanics, the first conceptually independent and logically consistent formulation of quantum mechanics.

1930 Paul Dirac published *The principles of quantum mechanics*a textbook that has become a standard reference work still in use today.

1935 Albert Einstein, Boris Podolsky, and Nathan Rosen publish an article emphasizing the counterintuitive nature of quantum superpositions and arguing that quantum mechanics’ description of physical reality is incomplete.

1935 Erwin Schrödinger, discussing quantum superposition with Albert Einstein, devises a thought experiment in which a cat (known forever as Schrödinger’s cat) is dead and alive at the same time; Schrödinger also coined the term “quantum entanglement”.

1947 In a letter to Max Born, Albert Einstein describes quantum entanglement as “spooky action at a distance” for the first time.

1951 Felix Bloch and Edward Mills Purcell receive a joint Nobel Prize in Physics for their first observations of the quantum phenomenon of nuclear magnetic resonance.

1963 Eugene P. Wigner lays the foundation for the theory of symmetries in quantum mechanics and for basic research into the structure of the atomic nucleus.

1976 Roman Stanisław Ingarden publishes one of the first attempts to create a quantum information theory.

1980 Paul Benioff publishes a paper describing a quantum mechanical model of a Turing machine, or classical computer, the first to demonstrate the possibility of quantum computing.

1985 David Deutsch of the University of Oxford writes a description for a quantum Turing machine.

1993 The first paper^{ }a description of the idea of quantum teleportation is published.

1994 Peter Shor develops a quantum integer factorization algorithm that has the potential to decrypt RSA-encrypted communications, a widely used method for securing data transmissions.

1996 Lov Grover invents the quantum database search algorithm.

1998 First demonstration of quantum error correction; first evidence that a certain subclass of quantum computations can be efficiently emulated with classical computers.

2004 First five-photon entanglement demonstrated by Jian-Wei Pan’s group at the University of Science and Technology in China.

In 2014, physicists at Delft University of Technology, Netherlands, teleport information between two quantum bits about 10 feet apart with a zero percent error rate.

2017 Chinese researchers report the first quantum teleportation of independent single-photon qubits from a ground observatory to a satellite in low-Earth orbit at a distance of up to 1400 km.

2021 University of Chicago researchers send entangled qubit states for the first time through a communications cable connecting a quantum network node to a second node.