Thu 22 May 15:00: A retelling of the Quantum Mechanics story
Typical accounts of Quantum Mechanics plot a path to the quantum world starting from a classical mechanics view point – ‘how do we translate momentum into an operator’ etc – , but this is fundamentally the wrong way round: it is impossible to derive an exact theory from an approximation so any attempt to do so results in a story with no coherence or substance in the way it is told. Here I propose an account that simply starts with the observations of how quantum systems behave, adding in special relativity, to develop the basic formalism and concepts of QM and show significant tracks of physics can be developed from just a few initial observations. A candidate is presented for the ‘simplest possible measurement’, proposing that there is no need for either an observer or a measurement device and suggesting that all quantum measurements are essentially an identical and remarkably simple, semi understandable, yet inexplicable, QM process. The basic premise of this approach is that if we are ever to extend our understanding of, for example, measurement and collapse, we need a clearer understanding of what we have in QM and on what it is based rather than ‘we make these unconnected guesses from classical mechanics, this is where we end up and, oh look, it works’, and whilst the author would not pretend to be delivering ‘the answer’, the hope is that this example of an attempt to do so will encourage others to consider developing more transparent explanations of the fundamentals of QM.
- Speaker: John Ellis, Surface Physics Group, Cavendish Laboratory
- Thursday 22 May 2025, 15:00-16:00
- Venue: Seminar Room West, Room A0.015, Ray Dolby Centre, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 01 May 15:00: The mechanical properties of wood at high rates of strain
Due to its importance in the construction of ships, wood was one of the first substances to have the velocity dependence of its resistance to impact quantified. This was achieved in England and France early in the 19th century. Techniques for measuring the high-rate mechanical properties of wood were developed around the start of the 20th century. These studies involved drop-weight and pendulum machines to quantify the dynamic fracture toughness of timbers and were mostly performed by the US Forestry Service. It was not until 1977 that the first high-rate compression stress-strain curves of wood were obtained using the Kolsky bar, despite this device having been developed in Britain in the 1940s. It took until the mid-1990s and the desire to use wood to cushion the drop-impact of vessels used to transport dangerous waste that Kolsky bar studies of wood began in earnest in Britain, the Czech Republic and Russia. Even so, to date fewer than 100 such studies have been published compared to nearly 5,000 for metals. The seminar will summarize the effects of anisotropy, stress state, multiple repeat loading, moisture content, temperature, and density on the high-rate properties of a wide range of woods. The seminar will finish with suggestions for what needs doing in the future. A review paper on this topic has recently been published in ‘Journal of Dynamic Behavior of Materials’.
- Speaker: Stephen Walley, PCS Group, Cavendish Laboratory
- Thursday 01 May 2025, 15:00-16:00
- Venue: Seminar Room West, Room A0.015, Ray Dolby Centre, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 22 May 15:00: A retelling of the Quantum Mechanics story
Abstract not available
- Speaker: John Ellis, Surface Physics Group, Cavendish Laboratory
- Thursday 22 May 2025, 15:00-16:00
- Venue: Seminar Room West, Room A0.015, Ray Dolby Centre, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 15 May 15:00: Prediction and its application to mechanical properties
Virtual representation of material response is increasingly common in design of novel materials as well as in attempts to understand observed response. Mechanical properties outside the elastic region are driven by complex interactions between microstructure and fundamental material physics and prediction carries a higher burden of trust. The intent to replace empirical methods with simulation only exacerbates this burden. Prediction and predictive methods in modelling and simulation will be discussed in the light of this complex situation.
- Speaker: Peter Gould
- Thursday 15 May 2025, 15:00-16:00
- Venue: Seminar Room West, Room A0.015, Ray Dolby Centre, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 08 May 15:00: Can we design fatigue-resistant alloys?
Better understanding of the origin and behaviour of fatigue cracks should lead to improved engineering design and alloying strategies for structural metals. The surface stresses caused by persistent slip bands, including a zone of infinite tensile stress at the edge of each band, seem an inevitable consequence of elastic non-linearity and hard to combat, except perhaps by the present expensive methods of shot-peening or surface removal. But the underlying process of jog movement to eliminate screw dislocation dipoles should be susceptible to control. It is important to understand better the main engineering problem: is design against persistent slip the metallurgist’s answer to crack-proof rotating machinery?
- Speaker: Mick Brown, Cavendish Laboratory
- Thursday 08 May 2025, 15:00-16:00
- Venue: Seminar Room West, Room A0.015, Ray Dolby Centre, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 01 May 15:00: The mechanical properties of wood at high rates of strain
Due to its importance in the construction of ships, wood was one of the first substances to have the velocity dependence of its resistance to impact quantified. This was achieved in England and France early in the 19th century. Techniques for measuring the high-rate mechanical properties of wood were developed around the start of the 20th century. These studies involved drop-weight and pendulum machines to quantify the dynamic fracture toughness of timbers and were mostly performed by the US Forestry Service. It was not until 1977 that the first high-rate compression stress-strain curves of wood were obtained using the Kolsky bar, despite this device having been developed in Britain in the 1940s. It took until the mid-1990s and the desire to use wood to cushion the drop-impact of vessels used to transport dangerous waste that Kolsky bar studies of wood began in earnest in Britain, the Czech Republic and Russia. Even so, to date fewer than 100 such studies have been published compared to nearly 5,000 for metals. The seminar will summarize the effects of anisotropy, stress state, multiple repeat loading, moisture content, temperature, and density on the high-rate properties of a wide range of woods. The seminar will finish with suggestions for what needs doing in the future. A review paper on this topic has recently been accepted for publication in ‘Journal of Dynamic Behavior of Materials’.
- Speaker: Stephen Walley, PCS Group, Cavendish Laboratory
- Thursday 01 May 2025, 15:00-16:00
- Venue: Seminar Room West, Room A0.015, Ray Dolby Centre, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 13 Mar 15:00: On the beamline: Studying surfaces at a 3rd generation synchrotron facility
From water adsorption on a hematite surface to 2D graphene networks on copper, the talk will focus on various surface studies performed at the I09 beamline of Diamond Light Source, the UK’s national synchrotron facility. The I09 beamline is a unique two-colour beamline utilising X-ray Standing Waves (XSW) which, as will be showcased, can probe element-specific adsorption heights, h, with high precision (Δh ≈ 0.02 Å).
- Speaker: Fulden Eratam, Diamond Light Source, Harwell
- Thursday 13 March 2025, 15:00-16:00
- Venue: Mott Seminar Room, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 01 May 15:00: The mechanical properties of wood at high rates of strain
Due to its importance in the construction of ships, wood was one of the first substances to have the velocity dependence of its resistance to impact quantified. This was achieved in England and France early in the 19th century. Techniques for measuring the high-rate mechanical properties of wood were developed around the start of the 20th century. These studies involved drop-weight and pendulum machines to quantify the dynamic fracture toughness of timbers and were mostly performed by the US Forestry Service. It was not until 1977 that the first high-rate compression stress-strain curves of wood were obtained using the Kolsky bar, despite this device having been developed in Britain in the 1940s. It took until the mid-1990s and the desire to use wood to cushion the drop-impact of vessels used to transport dangerous waste that Kolsky bar studies of wood began in earnest in Britain, the Czech Republic and Russia. Even so, to date fewer than 100 such studies have been published compared to nearly 5,000 for metals. The seminar will summarize the effects of anisotropy, stress state, multiple repeat loading, moisture content, temperature, and density on the high-rate properties of a wide range of woods. The seminar will finish with suggestions for what needs doing in the future. A review paper on this topic has recently been accepted for publication in ‘Journal of Dynamic Behavior of Materials’.
- Speaker: Stephen Walley, PCS Group, Cavendish Laboratory
- Thursday 01 May 2025, 15:00-16:00
- Venue: Mott Seminar Room, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 08 May 15:00: Can we design fatigue-resistant alloys?
Better understanding of the origin and behaviour of fatigue cracks should lead to improved engineering design and alloying strategies for structural metals. The surface stresses caused by persistent slip bands, including a zone of infinite tensile stress at the edge of each band, seem an inevitable consequence of elastic non-linearity and hard to combat, except perhaps by the present expensive methods of shot-peening or surface removal. But the underlying process of jog movement to eliminate screw dislocation dipoles should be susceptible to control. It is important to understand better the main engineering problem: is design against persistent slip the metallurgist’s answer to crack-proof rotating machinery?
- Speaker: Mick Brown, Cavendish Laboratory
- Thursday 08 May 2025, 15:00-16:00
- Venue: Mott Seminar Room, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 22 May 15:00: A retelling of the Quantum Mechanics story
Abstract not available
- Speaker: John Ellis, Surface Physics Group, Cavendish Laboratory
- Thursday 22 May 2025, 15:00-16:00
- Venue: Mott Seminar Room, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 15 May 15:00: Prediction and its application to mechanical properties
Virtual representation of material response is increasingly common in design of novel materials as well as in attempts to understand observed response. Mechanical properties outside the elastic region are driven by complex interactions between microstructure and fundamental material physics and prediction carries a higher burden of trust. The intent to replace empirical methods with simulation only exacerbates this burden. Prediction and predictive methods in modelling and simulation will be discussed in the light of this complex situation.
- Speaker: Peter Gould
- Thursday 15 May 2025, 15:00-16:00
- Venue: Mott Seminar Room, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.
Thu 15 May 15:00: Prediction and its application to mechanical properties
Abstract not available
- Speaker: Peter Gould
- Thursday 15 May 2025, 15:00-16:00
- Venue: Mott Seminar Room, Cavendish Laboratory.
- Series: Physics and Chemistry of Solids Group; organiser: Stephen Walley.