Quantum Public Lectures

Abstract

Superconductivity was discovered in 1911, before the theory of quantum mechanics was formulated in 1925. The physics of superconducting qubits was conceived in 1980, before quantum information science was widely acknowledged in the 1990s. From history, we learn how difficult it is to predict the progress of science and technology. Breakthroughs often occur at a level beyond our imagination.

Now, a quarter century after the first demonstration of a superconducting qubit, superconducting quantum computers exist to our surprise (or not?). They are still small-scale, error-prone, and not yet widely outperforming classical computers. There remain, not surprisingly, many challenges to be overcome before realizing a large-scale, fault-tolerant superconducting quantum computer. Control and readout of qubits must be fast and high-fidelity, and the overall scalability must be ensured from quantum processor units to packaging, wiring, cryogenics, control electronics, error correction, and software. New ideas are emerging, and technologies are evolving.

Abstract

Quantum technologies need photonics for scaling. This is true even for "non-photonic" quantum systems based on superconductors, or trapped atoms and ions in vacuum. For example, new types of spatial light modulators and switches are needed to trap and control atoms and ions, microwave to optical quantum transducers are needed for networking superconducting processors, chip-scale laser systems are required for controlling atoms or spin qubits in solids, and a very high efficiency integrated photonics is needed for quantum networks, sensors, and chip-based semiconductor quantum systems. Unfortunately, these photonics functionalities and performances are not available even in today's best integrated photonic systems. We show how inverse design (which combines AI hardware with new types of physics solvers) can lead to much better photonics designs, and how new photonic materials combined with new nanofabrication and heterogenous integration can lead to desired performances. Specific examples include development of miniaturized titanium:sapphire lasers on chip, strontium titanate transducers, quantum network nodes in diamond, and a quantum simulator and computer with silicon carbide color centers.

Abstract

With the invention of lasers, the intensity of a light wave was increased by orders of magnitude over what had been achieved with a light bulb or sunlight. This much higher intensity led to new phenomena being observed, such as violet light coming out when red light went into the material. After Gérard Mourou and I developed chirped pulse amplification, also known as CPA, the intensity again increased by more than a factor of 1,000 and it once again made new types of interactions possible between light and matter. We developed a laser that could deliver short pulses of light that knocked the electrons off their atoms. This new understanding of laser-matter interactions, led to the development of new machining techniques that are used in laser eye surgery or micromachining of glass used in cell phones.

Abstract

Clocks, in essence, are oscillators that we use to track the unrelenting passage of time. Higher frequency means more cycles and subunits of time per second, thus providing higher precision. Optical clocks represent this state of the art, where oscillations of electrons in atoms provide a measurement of the passage of one second that is equivalent to a billion years. After a general introduction to atomic clocks and their applications, this lecture discusses some of the most recent scientific advances, including applying quantum science to clocks by entangling atoms to improve their performance, and detecting dark matter and new physics via precision measurement.

Abstract

Anyone who is not shocked by quantum mechanics has not understood it, Niels Bohr allegedly once said. Indeed, the quantum world is radically different from the everyday world we experience. In the quantum world, objects do not have definite positions, particles can tunnel through walls, and cats can be dead and alive at the same time. Given that the microscopic world is governed by quantum mechanics, how do everyday properties of macroscopic objects arise from this strange quantum behaviour?

In this talk, I will explore this fascinating question. We will see the emergence of the classical world out of the quantum and will revisit the pivotal concept of "decoherence" understood as loss of quantum features when quantum systems become ever more macroscopic. The presentation will conclude by addressing the question: How large can quantum systems be in practice? By the end of the talk, I hope you will not only have a vivid idea of quantum weirdness, but also understand where the limitations of observing quantum features on large scales come from.

Abstract

Information technology has driven the breathtaking power of the Internet Age. Yet a quantum revolution is underway today that will replace "bits" (the zeroes and ones that represent data in conventional computers) with "qubits" – quantum bits that are both zeroes and ones. The payoff for successfully hacking nature will be new technologies that far outstrip the digital wonders of today. Quantum cryptography is already at the level of commercialization, offering communication security guaranteed by the laws of nature. The power of a quantum computer will far exceed even today's most powerful supercomputers, solving problems that would take these computers until the end of time – literally.

The impact of quantum information processing will likely be transformational, just as digital computing changed our world a half-century ago. It promises to bring computing power that will shed new light on weather systems and climate change; model and elucidate biological processes such as photosynthesis; break codes that are nowadays considered unbreakable; and simulate the action of drugs.

Abstract

We are entering a new era where quantum systems are starting to be employed for practical applications ranging from computation and communication to sensing and imaging. This talk explores recent developments at this science to technology interface and describes some of the current frontier challenges.

Abstract

One of a few members of the National Academy of Sciences whose research is in quantum information science, H. Jeff Kimble is a leader in the implementation of quantum information protocols. His research team and collaborators were the first to achieve quantum teleportation from one location to another.