quantum-field-theory

Experiments and theoretical analysis show that under extreme magnetic fields, electrons in zirconium pentatelluride behave in an unusual way that points to a topological origin rather than interactions among many particles. Under magnetic fields strong enough to push electrons toward their quantum limits, zirconium pentatelluride (ZrTe₅) did something conventional theory says should not happen. I…

An experiment by researchers at the University of California San Diego and TU Wien has revealed a new quantum regime that generates coherent X-rays at higher energies than conventional rules predict. When intense laser light strikes certain atoms, the atoms can respond by producing laser pulses at far higher frequencies, reaching into the X-ray range. [...]

Hello, I am reviewing standard literature on the Black Hole Information Paradox and Hawking Radiation (specifically starting from Hawking's 1976 paper and Susskind's Black Hole Complementarity). I have a foundational question regarding how observational limits are formally defined when... Read more

Calculating Imaginary-Time Evolution (ITE), essential for preparing quantum states and overcoming computational limitations, has traditionally demanded extra resources or risked inaccurate results. Now, a new approach sidesteps these issues by deriving ITE from standard measurements of real-time behaviour, offering an alternative pathway forward. This effectively links readily achievable simulati…

Suppose a Hilbert space has a direct-sum decomposition $$ \mathcal H=\bigoplus_{n\ge 0}\mathcal H_n, $$ where the sectors are eigenspaces of a self-adjoint operator $\hat S_c$ , $$ \hat S_c|\psi_n\rangle=s_n|\psi_n\rangle. $$ Let $\hat J$ be a self-adjoint generator of unitary evolution, $$ U(\tau)=e^{-i\hat J\tau}, $$ and suppose $$ [\hat J,\hat S_c]=0. $$ A separate clock/phase operator $\hat S…

The Hamiltonian of a free particle in a rotating frame is given by $$ H = H_0 - \omega \cdot J, $$ where $H_0$ is the Hamiltonian in the non-rotating frame, $\omega$ is the angular velocity of the frame and $J$ is the angular momentum of the particle. This relation is too beautiful to be a coincidence. Does it hold for arbitrary systems with rotational invariance? Is a more general statement poss…

Gravitational wave astronomy has seen plenty of improvements since the original signal was captured in 2015 . Despite that, it remains an engineering challenge to actually create the detectors needed for the precise measurements required to spot gravitational waves. A new NASA Innovative Advanced Concepts (NIAC) grant is funding a concept from a team led by Paul Stankus at Brookhaven National Lab…

Quantum technology could one day make communications more secure and sensors far more sensitive. But there is a major obstacle: many quantum systems only work at extremely low temperatures, requiring large, expensive cooling equipment. MIT researchers have now developed a small magnetic device that can produce strongly linked microwave signals at room temperature. The advance […] The post Scienti…

Coupled systems require complete quantisation to preserve relationships between position and momentum quantified by ħω representing energy in quantum fields. Analyses from Chiara Marletto London and Vlatko Vedral at the University of Oxford show combining classical and quantum descriptions introduces inconsistencies because