Sonic Analogs Research Articles

Opening the “Door”: A Multifaceted Approach to the Analysis of Text Setting in the Third Movement of Kate Soper’s “Door” (2007)

Abstract: The majority of Kate Soper’s (b. 1981) output as a composer-vocalist focuses intensely on the relationship between words and music. Methods of text and music analysis have primarily focused on relating musical materials to the semantic meaning of texts or have studied the ways composers musicalize sounds and use the materiality of poetry. Building on past scholarship and drawing from Soper’s program note to “Door” (2007), a setting of poems by Martha Collins for soprano, flute, tenor saxophone, accordion, and electric guitar, I develop a model that looks beyond semantics to investigate the roles of acoustic and aesthetic properties of words. My novel approach examines the relationship between music and words through four different but interrelated interpretive lenses: 1. Lexical, 2. Figurative, 3. Acoustic, and 4. Aesthetic. I demonstrate my methodology using the third movement of “Door” as a case study. I use Lexical interpretation to interrogate the piece-specific associations developed by Soper. My Figurative interpretation draws on the meaning of the words and extrapolates meaning from the poem before finding sonic analogues within the music. Acoustic interpretation involves inspecting the phonemes and acoustic envelopes of words and relating them to Soper’s choice of instruments. Finally, I observe which qualities of the poem and text resonate with me. Through Aesthetic interpretation, I attempt to understand what makes these qualities appealing. This multifaceted approach opens the door to consideration of new dimensions of comparison between text and music.

Density correlations from analog Hawking radiation in the presence of atom losses

The sonic analog of Hawking radiation can now be experimentally recreated in Bose-Einstein condensates that contain an acoustic black hole. In these experiments the signal strength and approximate analog Hawking temperature increase for denser condensates, which however also suffer increased atom losses from inelastic collisions. To determine how these affect analog Hawking radiation, we numerically simulate creation of the latter in a Bose-Einstein condensate in the presence of atomic losses, including nonunitary quantum field dynamics using the truncated Wigner approximation. In particular we explore modifications of density-density correlations through which the radiation has been analyzed so far. We find no evidence that losses directly alter the basic picture of the analog Hawking effect; instead all consequences that we find are indirect: Losses increase the contrast of the correlation signal, which we attribute to condensate heating by the losses, in turn leading to a component of stimulated radiation in addition to the spontaneous one. Other indirect consequences are the modification of the white-hole instability pattern and a change of slope of the Hawking tongue.

Particle scattering in a sonic analogue of special relativity

We investigate a simple toy model of particle scattering in the flat spacetime limit of an analogue-gravity model. The analogue-gravity medium is treated as a scalar field of phonons that obeys the Klein--Gordon equation and thus admits a Lorentz symmetry with respect to ${c}_{\mathrm{s}}$, the speed of sound in the medium. The particle from which the phonons are scattered is external to the system and does not obey the sonic Lorentz symmetry that the phonon field obeys. In-universe observers who use the exchange of sound to operationally measure distance and duration find that the external particle appears to be a sonically Lorentz-violating particle. By performing a sonic analogue to Compton scattering, in-universe observers can determine if they are in motion with respect to their medium. If in-universe observers were then to correctly postulate the dispersion relation of the external particle, their velocity with respect to the medium could be found.

Ghostly longing: Tonality as grieving in Bell Witch’s Mirror Reaper

Mirror Reaper, by the funeral doom metal band Bell Witch, is an immense 83-minute composition in which tonal organization plays an essential role in enhancing and creating meaning. Little analytical attention has been paid to doom metal; armed with a flexible conception of theories of tonal harmony and my full transcription of the album, I show that slow, repetitive music and rich engagement with musical details are not mutually exclusive. I present an analysis in which the tonal drama centres around slowly shifting bass support for a persistent melody F natural. At first, this F appears as a dissonant ninth over an E♭, then as a hollow fifth above a B♭ and finally as a consonant major third above D♭. I understand this progression as a sonic analogue for the grieving process that, according to interviews with the band, is the album’s main focus.

Sounding the Arcane: Contemporary Music, Gender and Reproduction

Reproduction is a central but largely unquestioned concept in sound and music studies, where it is typically used to refer to the capture, mediation, repetition, and distribution of sound via practices and processes of recording. However, reproduction has a variety of other meanings and connotations. In this article, I use reproduction as a critical apparatus through which to address contemporary music, its gendered formations, and its connection to contemporary social life. Contemporary music’s relationship with reproduction is contradictory, insofar as the disavowal of reproduction and reproducibility, and an ideological attachment to the ‘now’ and the ‘new’ have been central to its (re)production as a discursive formation. Yet reproduction is also central to contemporary music as a material practice. Making reference to Marxist feminist theories of social reproduction, I consider the relationship between contemporary music as a mode of artistic production and the ‘arcane’ of reproductive labour. I propose that Áine O’Dwyer’s Music for Church Cleaners functions as a sonic analogue for this relationship. I then consider contemporary music’s implication in reproductive crisis, as exemplified by The Industry’s experimental opera Hopscotch. The sonic disruption of the opera by anti-gentrification protesters in the Boyle Heights neighbourhood of Los Angeles serves to amplify contemporary music’s relation to reproductive crisis and the systemic functionalisation of artistic autonomy. In using social reproduction as a framework through which to both analyse music’s formal attributes and account for contemporary music’s changing organisation, circulation and social effects, I aim to provide an alternative theorisation of contemporary music, gender, capital, and social inequality.

Black-hole lasing in Bose–Einstein condensates: analysis of the role of the dynamical instabilities in a nonstationary setup

We present a theoretical study on the origin of some findings of recent experiments on sonic analogs of gravitational black holes (BHs). We focus on the realization of a BH lasing configuration, where the conclusive identification of stimulated Hawking radiation (HR) requires dealing with the implications of the nonstationary character of the setup. To isolate the basic mechanisms responsible for the observed behavior, we use a toy model where nonstationarity can be described in terms of departures from adiabaticity. Our approach allows one to study which aspects of the characterization of BH lasing in static models are still present in a dynamical scenario. In particular, variations in the role of the dynamical instabilities can be traced. Arguments to conjecture the twofold origin of the detected amplification of sound are given: the differential effect of the instabilities on the mean field and on the quantum fluctuations gives some clues to separate a deterministic component from self-amplified HR. The role of classical noise, present in the experimental setup, is also tackled: we discuss the emergence of differences with the effect of quantum fluctuations when various unstable modes are relevant to the dynamics.

‘Please could you stop the noise’: The grammar of multimodal meaning-making in Radiohead’s ‘Paranoid Android’

This article uses Zbikowski’s theory of ‘musical grammar’ to analyse Radiohead’s song ‘Paranoid Android’ from their 1997 album OK Computer. Invoking the close structural and compositional parallels between language and music, Zbikowski’s approach appropriates some of the core elements of cognitive linguistics to provide a means of ‘translating’ music into meaning-bearing conceptual structures via the construction of ‘sonic analogues’, which are a type of conceptual construct formed when incoming perceptual information is compared to existing cognitive knowledge stored as image schemas. The result is an analysis of the interactions between the linguistic and aural constructions of a multimodal text that not only sheds new light on the text’s meaning-making devices, but also endeavours to unlock the strategies through which such distinctive semiotic modes act and interact within texts to create meaning potential.

Quasi-steady radiation of sound from turbulent sonic ergoregions

Sonic Hawking radiation has recently been observed in dilute Bose–Einstein condensates (BECs), but it remains an open question whether this landmark achievement of atomic physics can lead to new insights into the effects on Hawking radiation of nonlinear back-reaction and new short-distance physics, as was originally hoped by Unruh when he introduced the sonic analogy. Furthermore, studies of sonic analog black holes have until now concentrated on (1+1)-dimensional scenarios, but Unruh’s sonic analogy for curved spacetime is only valid in more than one spatial dimension. We therefore model the evolution of a (2+1)-dimensional sonic black hole in a dilute BEC, over a long enough time to let the initial Corley–Jacobson instabilities saturate in vortex production and give way to a long-lived quasi-stationary state. In this quasi-equilibrium state we find the initial laminar ergoregion replaced by a turbulent zone that steadily radiates sound, but with a non-thermal power spectrum.

Acoustic Hawking radiation

A milestone for quantum hydrodynamics may have been reached, with experiments on a black hole-like event horizon for sound waves providing strong evidence for a sonic analogue of Hawking radiation.

Recent progress on analog gravity and related issues

Of the four kinds of fundamental interactions in nature, gravity is the first known to humankind, but at the same time, it seems to be the least understood. A self-consistent theory of quantum gravity is still elusive. Even though, the efforts to unify quantum theory and general relativity continue, and recent researches show that analog gravitational systems open up new possibilities for our understanding of the nature of gravity. The analog gravity provides us concrete non-gravitational physical systems to study the quantum effects in curved spacetime such as the Hawking radiation both theoretically and experimentally on the one hand, while on the other hand, the techniques dealing with issues in curved spacetime can also be applied to the analog systems themselves and shed light on them in return. In this paper, we review various analog models that capture different aspects of the behaviors of gravitational systems. First, we introduce the analog of the bending of light in curved spacetime with artificial metamaterials based on transformation optics, which is an analog of a classical general relativistic effect. We then review Unruhs sonic black hole model. When the speed of the background fluid is faster than the speed of sound in the fluid, one creates a sonic analog of a gravitational black hole. If the flow of an ideal fluid is irrotational, then the equation of motion describing the acoustic disturbance is identical to the dAlembertian equation of a minimally coupled massless scalar filed in a curved spacetime, which forms the foundation of the phonon Hawking radiation in analog systems. Unruhs sonic black hole model has become a paradigm for experimental verification of quantum effects in curved spacetime, and there have been, in recent years, many attempts to realize it in analogue systems such as the Bose-Einstein condensate, ion traps, optical fibers, and etc. Other related issues, such as the detection of modified vacuum fluctuations, which are intrinsically related to quantum effects in curved space, by means of superconducting circuit devices, and the metamaterial models of cosmological evolutions are also reviewed. Finally, we give an outlook for the future research.

Quantum Signature of Analog Hawking Radiation in Momentum Space.

We consider a sonic analog of a black hole realized in the one-dimensional flow of a Bose-Einstein condensate. Our theoretical analysis demonstrates that one- and two-body momentum distributions accessible by present-day experimental techniques provide clear direct evidence (i)of the occurrence of a sonic horizon, (ii)of the associated acoustic Hawking radiation, and (iii)of the quantum nature of the Hawking process. The signature of the quantum behavior persists even at temperatures larger than the chemical potential.

Voicing the Doge’s Sacred Image

During the fourteenth century, Venetian chronicles, art, and ceremony fostered provocative analogies between angelic annunciation and the political voice of the Venetian populace. Such analogies imagined a city whose civic and heavenly members were united through the sound of unanimity. At the intersection of the state’s civic and celestial bodies stood the doge, considered to be the image of the Republic and of its patron, Saint Mark. A complex of sung ceremonies and musical compositions addressed to the doge dramatized the notion that the voice, as a ritual instrument, could engender real political or spiritual change in the state and its leaders. Performances of acclamations to the doge positioned him within Venice’s sacred and civic hierarchies, while state art and ceremony forged symbolic resemblances between ducal acclamation and angelic annunciation. A repertory of occasional motets evidences polyphonic play with the notion that vocal rituals centered on the doge could activate the spiritual ideals of the state: the anonymous Marce, Marcum imitaris (c. 1365) draws a sonic analogy between spiritual likeness and musical imitation in order to dramatize the concept of the doge as Mark’s image, whereas Johannes Ciconia’s Venecie mundi splendor/Michael qui Stena domus elides a text dedicated to the Annunciate Virgin with one addressed to the doge, creating musical echoes and simultaneities in its praises of Venice’s temporal and celestial leaders.

A black-hole laser

Astrophysical observations of Hawking radiation may be out of reach, but evidence for the self-amplification of Hawking radiation has now been observed in a sonic analogue of a black hole.

Dumb holes: analogues for black holes

The use of sonic analogues to black and white holes, called dumb or deaf holes, to understand the particle production by black holes is reviewed. The results suggest that the black hole particle production is a low-frequency and low-wavenumber process.

Detection Scheme for Acoustic Quantum Radiation in Bose-Einstein Condensates

Based on doubly detuned Raman transitions between (meta)stable atomic or molecular states and recently developed atom counting techniques, a detection scheme for sound waves in dilute Bose-Einstein condensates is proposed whose accuracy might reach down to the level of a few or even single phonons. This scheme could open up a new range of applications including the experimental observation of quantum radiation phenomena such as the Hawking effect in sonic black-hole analogues or the acoustic analogue of cosmological particle creation.

The sonic analogue of black hole radiation

A microscopic description of Hawking radiation in sonic black holes has been recently presented (Giovanazzi S 2005 Phys. Rev. Lett.94 061302). This exactly solvable model is formulated in terms of one-dimensional scattering of a Fermi gas. In this paper, the model is extended to account possible finite size effects of a realistic geometry. The flow of particles is maintained by a piston (i.e. an impenetrable barrier) moving slowly towards the sonic horizon. Using existing technologies the Hawking temperature can be of the order of a few microkelvin in a realistic experiment.

Hawking Radiation in Sonic Black Holes

I present a microscopic description of Hawking radiation in sonic black holes. A one-dimensional Fermi-degenerate liquid squeezed by a smooth barrier forms a transonic flow, a sonic analog of a black hole. The quantum treatment of the noninteracting case establishes a close relationship between sonic Hawking radiation and quantum tunneling through the barrier. Quasiparticle excitations appear at the barrier and are then radiated with a thermal distribution in exact agreement with Hawking's formula. The signature of the radiation can be found in the dynamic structure factor, which can be measured in a scattering experiment. The possibility for experimental verification of this new transport phenomenon for ultracold atoms is discussed.

Non-Riemannian geometry of vortex acoustics

The concept of acoustic torsion is introduced by making use of the scalar wave equation in Riemann-Cartan spacetime. Acoustic torsion extends the acoustic metric previously given by Unruh (PRL-1981). The wave equation describes irrotational perturbations in rotational nonrelativistic fluids. This physical motivation allows us to show that the acoustic line element can be conformally mapped to the line element of a stationary torsion loop in non-Riemannian gravity. Two examples of such sonic analogues are given. The first is the stationary torsion loop in teleparallel gravity. In the far from the vortex approximation, the Cartan torsion vector is shown to be proportional to the quantum vortex number of the superfluid. The torsion vector is also shown to be proportional to the superfluid vorticity in the presence of vortices. The formation of superfluid vortices is shown not to be favored by torsion loops in Riemann-Cartan spacetime, as long as this model is concerned. It is suggested that the teleparallel model may help to find a model for superfluid neutron stars vortices based on non-Riemannian gravity.

Cosmic Problems for Condensed Matter Experiment

Condensed matter analogs of the cosmological environment have raised the hope that laboratory experiments can be done to test theoretical ideas in cosmology. I will describe Unruh's sonic analog of a black hole (``dumbhole'') that can be used to test Hawking radiation, and some recent proposals on how one might be able to create a dumbhole in the lab. In this context, I also discuss an experiment already done on the Helium-3 AB system by the Lancaster group.

Hawking Radiation in the Laboratory

We propose an experimental model using the Laval nozzle of a sonic analogue of Hawking radiation. We derive the power spectrum of the outgoing wave emitted from the vicinity of the sonic horizon instead of the created particle number. Our treatment is based on classical theory, and it should make experiments easier to implement. This experimental feasibility is a great advantage of our model.