PhD projects

Prospective graduate students should apply through the university’s admissions website, but are encouraged to first discuss their plans with Dr Laird.

Advertised projects for 2022

These are some of the projects for which we are currently seeking PhD students. Research moves fast, and this list doesn’t keep up. If you are interested in working in one of our research areas but don’t see a project there, please contact Dr Laird anyway.

Detecting, identifying, and locating GPS jammers

Jamming of satellite signals, by accident or design, is an increasing threat to transport infrastructure. In this joint project between Forsberg Services Ltd and Lancaster Physics Department, we are developing a device that will rapidly locate jammers based on measurements of their signals from different receiver locations.

Satellite navigation by GPS and its equivalents is a cornerstone of modern transport infrastructure. However, satellite navigation signals are easy to jam. Operators of ports and airports regularly encounter inadvertent jamming from leaky electronics and deliberate jamming by criminals who are trying to avoid being tracked by their employers or the police. They are also at risk of more serious attacks by saboteurs or terrorists.

This studentship (for which we have applied for support via the CASE scheme) will devise reliable ways to locate jammers using a combination of physical insight and data processing. Your time will be divided between the Physics Department and Forsberg’s site in Heysham. This is an exciting opportunity to apply your knowledge of physics to an important challenge in engineering, and to work at the interface between the university and the technology industry.

Quantum electronics for an axion detector

(with Yuri Pashkin and Ian Bailey)

Schematic of an axion detector. By generating a strong magnetic fields, we induce passing dark-matter axions to decay into photons (see inset). These photons are trapped in a microwave cavity, collected by an antenna, and amplified to generate an electrical signal whose power spectrum should reveal the axion mass. Critical to the experiment is a quantum-limited amplifier, which this project will develop.

One of the greatest challenges in physics is to identify the dark matter that makes up 80% of our galaxy’s mass. Among the leading candidates is a hypothetical particle called the axion. This is a well-motivated addition to the Standard Model but is very difficult to detect because it is predicted to interact feebly with ordinary matter. This project will develop quantum amplifiers in a new UK experiment that will search for axions.

If axions exist, then in a strong magnetic field they can decay into photons with frequencies proportional to the axion mass. However, the resulting electromagnetic signal is expected to be extremely weak – comparable to intrinsic quantum fluctuations, and weaker than thermal radiation except at the coldest accessible temperatures. This project aims to detect evidence of axions by developing and using superconducting amplifiers that can approach and ultimately exceed the standard quantum limit of detection sensitivity.

The student will work within the Quantum Sensors for the Hidden Sector Collaboration, which is an STFC-funded project to search for axions and axion-like particles (ALPs) using advanced quantum electronics and quantum measurement techniques. The collaboration works with the Axion Dark Matter Experiment (ADMX) in the USA, which currently leads the world in sensitivity to dark matter axions. We aim to develop a novel high-frequency axion target to be incorporated into the existing ADMX apparatus, as well as developing our own cutting-edge research instrumentation for axion and ALP research in the United Kingdom. The student will have the opportunity to develop research experience in a range of areas across quantum electronics, microwave electronics, cryogenics, magnetic field physics, quantum systems theory, and particle theory and phenomenology. They will join the collaboration as it embarks on this exciting new programme of inter-disciplinary fundamental research in the UK.

Nanoelectromechanical sensors for magnetic resonance microscopy

The proposed magnetic resonance force microscope. A nano-magnet is suspended from a vibrating nanotube and positioned close to the specimen. Inverting the nuclear spins in the specimen generates a magnetic field which deflects the nano-magnet. From sensitive measurements of the displacement, an image of the specimen is constructed.

Magnetic resonance imaging (MRI) is a powerful and non-invasive technique for looking inside the human body. If we could make a microscope that works on the same principle, we would be able to do something that is presently impossible – to look inside cells, viruses, and potentially even individual molecules and identify the atoms from which they are made. Unfortunately, MRI machines cannot simply be made smaller, because as their radio antennas are shrunk they become less sensitive. For this reason, the resolution of conventional MRI is still far below that of other kinds of microscope.

To develop an MRI microscope, we need to develop a new kind of device that measures the same effect with much higher resolution. Such an approach is magnetic resonance force microscopy. In this technique, a tiny nano-magnet is attached to a delicate mechanical spring and positioned as close as possible to the specimen being measured. As the nuclei in the specimen precess, their magnetic field deflects the nano-magnet, thus creating a measurable signal.

To construct a microscope based on this principle is still a formidable challenge. For each nucleus in the specimen, the force exerted on the nano-magnet is roughly one zepto-Newton. We aim to detect such a force by using the lightest, most delicate spring that can be fabricated – a single carbon nanotube. This project will develop nanotube force sensors and the associated quantum electronics to measure them. The two central physics challenges are to attach a nano-magnet to a nanotube spring and to measure its tiny deflection. To overcome them, we seek highly motivated graduates in physics or related fields with curiosity, grit, and a passion for making new discoveries through experiment.

Within this project, you will work in the Low Temperature Physics and Quantum Nanotechnology groups at Lancaster. You will receive a thorough training, supported by state-of-the art equipment, in quantum electronics, low-temperature physics, nanofabrication, and scientific communication. Through your research in this project, you will have the opportunity to contribute to a physics-based technology with profound potential in materials science and biology.

References (see Publications)

  • “A coherent nanomechanical oscillator driven by single-electron tunnelling”, Y. Wen et al., Nature Physics (2019)

Studying quantum motion with a vibrating carbon nanotube

The “displacemon” proposal for measuring mechanical quantum interference. The wavefunction of a vibrating beam is separated and recombined to generate interference fringes.

To predict the behaviour of a small particle, for example, an electron moving through a molecule, it is essential to use the concept of quantum superposition – the particle may traverse a superposition of multiple paths simultaneously. Such superposition states have been beautifully demonstrated for tiny objects such as photons, atoms, and molecules, but it is an exciting open question why larger objects do not show this behaviour.

We can address this question experimentally by studying the motion of mesoscopic objects containing millions of atoms. This project will make and measure vibrating carbon nanotubes. A nanotube acts like a vibrating string, but with a resonant frequency so high enough that it can be cooled near to its quantum ground state. We recently showed theoretically how to create an analogue of a grating interferometer, constructed by integrating the resonator into a superconducting qubit. This should make it possible to measure interference between different paths of motion. Achieving this in a real experiment would dramatically push the boundary of quantum mechanics from the realm of molecules towards the realm of fabricated objects. This project will aim to carry the experiment out, using advanced cryogenic and nanofabrication technology at Lancaster. It will involve advanced training in low-temperature physics, quantum electronics, and nanofabrication.

References (see Publications)

  • “Displacemon electromechanics: how to detect quantum interference in a nanomechanical resonator”, K. Khosla et al., Physical Review X (2018)

A miniature atomic clock using endohedral fullerene molecules

Atomic clocks are the most precise scientific instruments ever made, and are key to advanced technologies for navigation, communication, and radar. The most accurate atomic clocks cost millions of pounds and take up entire rooms, but an important goal for this research field is to develop miniature, portable clocks. This is a major challenge for quantum science and technology.

This PhD project will pursue a new approach to create a clock that will fit on a chip. Present-day atomic clocks are based on atomic vapours confined in a vacuum chamber. Our new approach is to use electron and nuclear spins in endohedral fullerene molecules – nature’s atom traps – whose energy levels offer an exquisitely stable frequency reference. To make this novel approach work, we must overcome a range of physics and engineering challenges, including detecting spin resonance from a small number of spins, identifying the energy levels involved, and miniaturizing the control electronics and magnet. The reward will be a completely new technology with a wide range of civilian and military uses. We are looking for a candidate who has a strong interest in applying quantum physics in new technology and is motivated to develop the new and demanding electronic measurement techniques that will be necessary.

References (see Publications)

  • “Keeping Perfect Time with Caged Atoms”, K. Porfyrakis and E.A. Laird, IEEE Spectrum (Dec 2017, p34)
  • “The spin resonance clock transition of the endohedral fullerene 15N@C60”, R.T. Harding et al. Phys Rev Lett. 119 140801 (2017)